It's kinda useless. Mouse wheel could be much better utilized to e.g. set the instrument volume on a per-note basis (I know about alt-click, I'm talking about much finer control).
Just chiming to say that I love the mouse wheel zoom feature and I use it all the time, I edit on a TV that's a bit far away to see details and the zoom feature makes it seamless. +1 from me for leaving the option to toggle it back on!
Yes, with a wireless mouse/keyboard. It's for games/movies, but 1BitDragon makes it so easy to just start poking around at a song, that I can often find energy to be creative and work on game music in an evening, even if I'm too tired to do any programming.