Why? That just doesn't strike me as being very cost effective.
If the plan is to sell a pack of 4 sleeves for $10 to go with a pack of 4 alkaline batteries ($3 for Rayovac, $6 for Duracell around here), you could instead buy 4 Panasonic eneloop Ni-MH AA batteries for $13. You would, admittedly, have to pay for a charger and charge them beforehand, but you'd save lots of money over the life of the rechargeables. The Panasonic chargers go for between $7 and $14, but I highly recommend a La Crosse Technology brand recharger with LED displays and more sophisticated modes and options. -- they run around $35 to $40 on Amazon.
I've had nothing but eneloops for about 7 years now - they run in my electric toothbrush, my remotes, mouse and keyboard, etc. They're rated for over 2,000 charges each and I'm nowhere near that limit. As for voltage, they're designed to have a lower internal discharge rate than most rechargeables and a much higher and more stable voltage than most alkalines -- typically staying above 1.1 volts 'til they "die" and require a recharge. This means they last longer both when the device is not in use (not draining while resting), and last longer while in use because the voltage doesn't drop until it's drained.
I only had a problem with one device -- its tiny form-factor wouldn't let me squeeze the eneloop AAs inside as they're slightly thicker than a regular AA.
I've tried many rechargeables for decades and many were failures - largely because they failed to hold a charge or recharge well at all. Eneloops changed the game for me. They were originally made for cameras that required a higher stable voltage and used to be quite expensive, but the prices have dropped drastically.
Now, I haven't researched others as I haven't had to buy a AA or AAA in 7 years, but I'm sure there are others out there that perform as well or better by now.
Not the most scientific review, but here's one example of testing them against alkalines and other rechargeables:
Notice specifically the yellow voltage line for the eneloop AA rechargeables. After about 3 hours, all batteries dropped to 1.2 volts, but the eneloop stayed there longer and continued to stay between 1.1 and 1.2 volts for about 5 more hours while almost all the rest dropped off. Looks like the Varta ready2use NiMH beat them on overall life, but not by much.