I only ever charge my iPhone at night next to my bed, if I just have to put the watch on the charging stand (or whatever) at the same time as my phone I don't think people are going to care too much.
They will need enough battery life though to go from morning to the next morning I would say, as you don't exactly want to have your watch stop working after a night of drinks after work...
That's immediatly the biggest mistake from the Moto360, the watch looks awesome... But the battery life is too short :(