Some also argue that executing UI logic of every widget is wasteful. This might indeed be a concern when implemented poorly
For a game, which is already quite busy even when "idle" (and there are probably other things going on in each frame which take far more CPU and GPU to render), it won't be much of a concern; but with an application where most of the time is spent waiting for user input, spinning the CPU to re-render the GUI every frame is very energy-inefficient.
For a game, which is already quite busy even when "idle" (and there are probably other things going on in each frame which take far more CPU and GPU to render), it won't be much of a concern; but with an application where most of the time is spent waiting for user input, spinning the CPU to re-render the GUI every frame is very energy-inefficient.