It doesn't seem like there's much ongoing work on suyu, which isn't surprising since emulators are difficult to develop. Not many people have the necessary knowledge and are willing to work for free.

So yes, suyu is there for people who need it for it's performance, but it seems likely that Ryunjinx continues to improve while suyu won't change much in terms of performance and compatibility.

It's great for the games that are already running well though, especially on low end hardware like the Steam Deck.