For minimize, whether it's a line that shrinks, a genie lamp, a simple shrink effect, it's all the same. A simple visual cue telling you where it went.
A little form with the function is fine with me. There's a ton of computing power in even the weakest of machines. That said, I hope we'll always be able to turn it off.
Even a default install of Raspberry Pi OS uses a composited window manager on the RPi 4 now.
Why is this desirable? Objects in the real world have many inconvenient properties.
When you release a new OS version it has to look fresh or nobody will want it.
What's worse is, (at least IMO) they aren't even particularly pretty.
But about half of Linux YouTubers proudly display them. (Between you and them, the clueless one isn't you.)
It seems like once the graphics capabilities became common, OS interface developers used them even when they shouldn't have. Remember when moving windows in Linux had a "jiggle" to them? The genie effect in OS X? What about the "cube" of multiple desktop? I still don't know what the point of transparent windows is.
A few effects are useful - like aero peek in Windows.