It is true that you need to put the silly thing into developer mode to do anything "fun" to a chromebook, but the decision to LEAVE it in developer mode is up to you.
There is a custom firmware called MrChromebox, which is fairly painless to install. (you DO need to open the chromebook and remove the write protect screw temporarily to do a full system flash) However, in many cases, you can do a full system rom replacement, which completely removes "Developer mode" altogether. You get a pretty stripped down UEFI implementation of coreboot instead.
I recently did this to an HP chromebook for a coworker, who wanted to use her chromebook as a low-tier windows PC. (Her model has an actual NGFF ssd inside it, rather than the eMMC shit in most modern ones.) She loves the thing post-conversion.
Even if you dont do a full system replacement, you can add the "boot legacy OS" module on, then push some arguments into the flash rom to tell it to skip the key combos, effectively removing the thing you are objecting to. (This is what I have done with my Celes, which does not currently support full UEFI replacement.)
I am digging the shit out of GalliumOS. (A fork of xubuntu tailored specifically for hacked chromebooks.) It works like any other low-tier linux machine, and since my chromebook is x86 based, I am use WINE, and run some limited windows software, as needed. (mostly some older games, like DIablo II and the like.)
If you have a big enough eMMC/NGFF storage inside, you can even dual-boot chromeos and galliumOS. (Just be aware that you will certainly need to use a class 10 microSD card for /home, with tmpfs mounts on commonly written areas, like the browser cache, since the storage inside most chromebooks is in the "16gb total" neighborhood.) For systems with real NGFF SSDs, this can be a real treat, with no real trade-offs.
The basic point here being that you can open the lid on these tin-cans without leaving that "factory wipe" sword of damoclese hanging around. The choice to leave it is entirely on you, as the option to remove it is available.