I’d already been working on a Tildes app for a while before knowing Reddit was going to kill third-party apps. I didn’t have time to work on Lemmy and Tildes and RIF.
Since Tildes is different enough, it made sense at the time to have both a Tildes and RIF app which didn’t have too much overlap; their communities are quite different. Lemmy and RIF are more similar to each other.
Who knows; after I release my Tildes app, I could work on other apps too.