This exactly.

I don’t want an extra launcher/downloader thing that keeps on running in the background.

When I want to play the game, I want to only have to start the game itself. That on top of the fact that Linux can have significantly less bloat than Windows, is a big +.
I even experimented with turning off plasma and playing the game directly in X11 without even a WM. Though it turned out not to make a big difference since the DE seems to be light enough to not be a problem.

Even in case of Steam, the only times I want to have to run it is when I am opening the store or updating the games. Not when I just want to play it and definitely not for a Linux native game which does not require Proton nor the runtime.

So, if there are enough people like me, the client would be a wasted effort.

Her problem was that her fans would then see a Samsung phone in the social pics, instead of the seasonal variety ornament that is the iPhone.