In Linux I use SysReq to do a low-level reboot of the system and to kill excess tasks via "Magic SysReq" commands. Also, there many 3D design programs that use those keys for some special functions. I am not a fan that this functionality is buried by the C64 commands. However, I do like that I can restore this visible labeling by just adding it back by having WASD Keys make me a key cap for it. Yes, its going to be pricey, but I am happy to pay to keep having the option to have options.
Thanks for explaining the functionaility you are aware of -- I find it useful to know what the intended purpose was of these keys.