If you have translucent title bars enabled,¹ you may have noticed that the translucency goes away when you maximize a window. Why is that?
This is a performance optimization.
Opaque title bars are more efficient than translucent ones, and when you maximize a window, you're saying,² "I want to focus entirely on this window and no other windows really matter to me right now." In that case, the desktop window manager doesn't bother with translucency because you're not paying any attention to it anyway.
This may seem like a very minor change, but the difference is noticeable on benchmarks, and, like it or not, magazine writers like to use benchmarks as an "objective" way of determining how good a product is. The reviewers choose the game, and we are forced to play it.
¹The desktop window composition feature that provides the translucent title bar probably has some official name, but I can never remember what it is and I'm too lazy to go find out.
²This may not be literally what you're saying, but it's how the window manager interprets your action.
[Raymond is currently away; this message was pre-recorded.]