I agree that many pool players could benefit from being more like snooker players. That particular video gets a few things wrong and misses what seems to be a very important part of Ronnie's technique on power shots.... However I'll get a little more specific in this case and say to watch a few vids of Ronnie O'Sullivan cue action break downs....
I think the main benefit from having the chin on the cue is that your head is in the same place relative to the cue on every shot. I think that even if you do not have the cue in the "best" position as far as seeing the shot accurately, having the same view on every shot is huge for developing consistency. The second most important benefit in my view is that there is tactile feedback during the stroke of the position of the cue. That requires the chin to remain in contact during the forward stroke.