It is useful to have a hard key function for this, and I think they've done it out of necessity. Let me explain:
With the TP2, screen alignment settings are saved in such a way that the five points are read into Bootloader and are then passed to the OS on start-up. If you do a hard-reset you will notice that you will not have to re-align your screen, as it simply takes the previous values.
Now, with that information, imagine someone aligned your screen incorrectly in such a way that it was impossible to get to the correct menu. (there is actually space outside the visible screen area that is touchable and it can screw everything up) Therefore having a hardware key to allow someone to re-align their screen becomes necessary.
I hope I've explained it well, and although you may not like their key choice, too bad
.