Mainly to aid switchers I think. PC users do not really use an analogous key to do what Macs can do with the various command-click shortcuts. So, in order to make things easier to explain to new users, the Apple was removed and replaced with the verbiage "command" on the key about a year ago so newbies would know what we meant when we provide keyboard command instruction.
i just noticed this the other day! what a shame! that button's been on Apple key boards as long as I can remember, and probably since before I was born. I guess I'll never upgrade my early '07 MBP.