When they take up a substantial fraction of the time playing a casual game? Yes, they become important. If I can't pick it up and quickly play N games whilst I'm on the train of a morning, I'm not interested, sorry. If I wanted long load times and faff between games, I have a whole Steam library full of that.
So you have to tap twice in between games instead of once. If this is anything approaching a significant fraction of your time playing Threes, then you are terrible at it. It takes a good 10-20 minutes to get up to a 768 or 1536.
