yes, you wouldn't be able to run more than about 450 such apps concurrently on the pi before they started to get slower. (if you were concerned about battery life, you wouldn't be using a pi; there are alternatives with orders of magnitude lower power usage, some of which can even run linux. but there's no way for a pi to use an amount of energy that's significant next to a human being, let alone a refrigerator or a car)
but 9% is really very pessimistic. 0.05% is a more realistic number
users are 100% entitled to spend their resources on whatever apps they think is worthwhile, and of course to spend their time programming their computers as inefficiently or efficiently as they want
9% from one app, 9% from another, pretty soon we're talking about real power consumption / battery life
And even the 9% that you find trivial is something I, as an user, could use for something that gives me a benefit instead of your game-like GUI.
> so it makes sense to trade off cpu consumption and ram usage for faster experimentation in a lot of cases
It does not. If it has nothing animated, you'd better not redraw it. Anything else is lack of respect for the user's resources.