Talklittle themself has said that it’s actually because they were already working on a tildes app before the reddit API changed. Tildes was different enough from reddit that they felt comfortable investing the time. Then 3rd party apps got booted and everyone started moving over, and at that point it was easier to keep working on the same tildes app than to start anything new.
Why not make a needlessly tall and unruly one that can fit all 10? :D