I’m actually really glad that Letterboxd only has movies and doesn’t dabble in TV shows as well, but I always see TV shows popping up (before eventually being removed). Might just be me though.
That said, I too would pay $20 for a real Letterboxd app, even if I don’t mind their mobile site. At least integrate into one of these movie tracking apps. Until that happens though, I’ll just keep using the Letterboxd site.