Yes, I'd like to mess around with tablet games and similar too, don't get me wrong, but I don't see it as a preferable target platform over desktop computers for aforementioned reasons.
The plus of Linux and Mac support is that you can (more or less) easily deploy your PC game on three other platforms as well while you'd have to develop separate games for tablet/ mobile and PC (and everyone knows how hard it is to develop a game for a single platform).