There are for sure other people that play in suit, I've spoken with a few of them. I wouldn't call it rare, at least in the overlapping circles of "plays DDR at least semi regularly" and "has fursuit".
It's like, a dumb idea. Like it looks cool but being in fursuit is already exhausting and sweaty and doing DDR on top of that is just, a lot. I guess dancing (normal) in fursuit is the same but that is usually more appealing to the average person... that watches people in fursuit or whatever.
I'm the only person I've ever seen play doubles in suit, and most people I've seen play in suit will use bar as well, which is just a very different way of playing. I'd love to see more people play the way I do, no bar doubles with emphasis on body flow (ideally), because if nothing else that means I get to see it without having to do it myself.
But I also just think everyone should play that way. It's very fun. Doubles is super overlooked. But as with most things with DDR, accessibility is a huge issue.