Yeah, you have to be careful when to use it -- against an opponent who uses it too much all you have to do is make a threat with a move, and even if the move is suicidal, premove will force him to ignore it :)
I'm thankful for pre-move at the end of a 5 or 15 minute game where I'm winning, but I've used about all my time getting there.
btw, great pattern recognition for 1 minute chess -- especially in the opening it's easy to start moving too fast -- although sometimes this site's 1 minute chess is more like 3 minute chess 
People who pre-move unforced moves make me laugh. It's almost too easy. Especially the ones that play the same premoves game after game.
In one minute chess, you almost must use premove, but watch out (5...c6 is losing, requiring 6...Be6):