I've seen cases of both - cool and distracting. In the mid 2000's(?) Marvel or DC(or both, my memory is hazy on it, haha) were pushing motion comics(!) as the next Big Thing, but as far as I know it never went anywhere. But I know over the years I've seen a few webcomic-instances of it that were really cool.
I dabbled in it a few times, too. It was fun to do. I would definitely stress that less-is-more, if you decide to play around w/ it. It's a bell or a whistle - and certainly second fiddle! - to a good story and good art, and should probably be treated as such. But it can be fun! Have fun! 