I think some plugins rely on having a desktop theme made to accommodate them otherwise you’d have to do the themeing yourself. Thankfully there are plenty that already exist which can be downloaded and applied from within Playnite itself but I do agree that the experience can be a bit of a mess. I really can’t live without it, though. Just completely changed the way I organize and launch games forever.
You’re forgetting the part where you’re the extreme minority and so you don’t really matter much to the market.