I had a friend who had a Benjamin, actually, but this was back in the 60's, and yes, I was jealous as I had only a .177 break-action pellet rifle. Speciality pellet that had, as you note, a muzzle velocity "comparable" to a 22 short. Yes (Google being Our Friend), 22 LR is 1200 fps (for a reason!), a 22 short is around 1000 fps, and a Benjamin is (usually, dependent on model and mechanism) 900, which is quite respectable but depends on pellet weight.
When I decided as an Old Guy to get a really good hunting class pellet rifle I looked hard at the Benjamin-Sheridans but ended up picking the Walther Falcon Hunter edition, which is also 900 fps and fires a variety of standard or "hunting class" .22 pellets. I actually haven't tried to fire it through a 4x4 -- but who knows? I got it for my sons (really, my youngest son who is the most avid hunter) and it drops a rabbit as readily as a 22. I'm guessing that a hollow point pellet would quite possibly kill a deer shot at reasonably close range (10 yards or so and a heart or perfect head shot) -- as a 22 might -- or for that matter a human. I doubt it would "drop" either one, though and this is something I would never try with either rifle, of course, unless it is after the apocalypse and it is kill a deer with the pellet rifle or go hungry:-). In the old days I saw for myself that a daisy BB gun would leave a very painful divot in human skin without quite penetrating (no, I did not pull that particular trigger). You would not try that with the Walther as it would go clean through your leg if it didn't hit the bone, and would have a pretty good chance of chipping or breaking the bone.
The Walther, in other words, like the Benjamin Marauder etc, is definitely not a toy gun. I also have an older .177 caliber pellet gun that fires a pellet slowly enough that you can "see" it (barely) en route and one doesn't fire it at a plywood sheet as it might bounce back (or more likely, embed itself 3 mm into the wood). No comparison.
Bear in mind that it isn't just muzzle velocity, it is mass. A .22 LR is typically a 40 grain bullet, a .22 short is around 30 grain, compared to a "standard" .22 pellet at 14.3 grains and speciality hunting pellets at 20 to as much as 40 grains). The .22 LR has around 5x the kinetic energy of almost any pellet rifle out of the bore and that's a simple fact. Finally, it is ballistic drag. Pellets generally aren't fired fast enough to get sufficient stability from rifling and spin to be particularly accurate, which accounts for their "diabolo" waist. This also produces substantial drag -- it is being stabilized by drag. This means that pellet rifles have a rapid dropoff of their muzzle velocity and are really only suitable for short range hunting for any sort of larger game. Real .22 rifles get enough spin that they can avoid the skirted diabolo design, avoid much of the drag, and still have equal or better precision and ballistics. The third issue is the sound barrier. That's the thing that limits .22 muzzle velocity even in the case of the rifle -- there is substantial turbulence as a bullet passes through the sound barrier slowing down, and one needs streamlined bullet shapes like those found in centerfire rifles (which do indeed fire even .22-ish caliber highly streamlined and much more massive bullets with muzzle velocities well over the speed of sound) to have decent ballistics. Rimfire .22 LR bullets are not streamlined and are designed to shoot just under the speed of sound (or in the case of 1200 fps almost instantly drop down under it as the bullet "settles" out of the barrel) so that they usually have decent but not impressive precision (bench grouping). Competition grade guns (rimfire or pellet) usually shoot bullets at muzzle velocities deliberately well under the speed of sound -- .22 shorts, not long rifles, for example. The needs of hunters -- high muzzle velocity at a substantial pellet mass, decent ballistics, high bullet energy -- are not always compatible with maximum precision at range. 900 fps .22 is a decent compromise, but the Benjamin Marauder (which absolutely is a very high end hunting class rifle) can come in a .25 caliber and can fire much heavier pellets. I have 20 grain pellets for the Walther -- I am guessing that they drop my muzzle velocity some but not too much -- and CAN get much heavier pellets, basically up to 40 grains, equivalent to shooting a .22 LR bullet out of the pellet gun. At that mass, however, the muzzle velocity would be substantially lower. Good perhaps for high precision target shooting at shortish ranges or game at those ranges, not so good for 30 to 50 yard shots. But then, pellet rifles are rarely particularly "good" for shots longer than 30 yards.
At 900 fps one has a wide range of "hunting" class rifles with similar muzzle energies to choose from, that are all going to have very similar ballistics and penetration capabilities at similar ranges, because most of the stuff that happens is pure physics. You can pay more for features -- especially precision-enhancing features or precompression, as those things require more engineering. The Walther isn't the most expensive hunting class rifle made, but it is a damn good intermediate one and, if you look around with Google, a very popular one for good reason. One could argue that it is one of the best values out there -- basically the same muzzle velocity as the Benjamin and other very high end guns, extraordinarily good stability and balance, simple mechanics and capable of high precision (small grouping) at 20-30 yards (it is actually a break action rifle -- single spring pump) and very high reliability. With a 20 grain hollow point pellet at 20 yards, easily the match of any small game including foxes or racoons or groundhogs (none of which we would likely shoot where I live) and perfect for rabbits and squirrels or birds.
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