Sync UI/UX are carried over from years of refinement as a Reddit client with full native controls. It now mostly just has a different API and service layer wired in for Lemmy. Definitely not a simple web view app.
I really wanted to just use the PWA, but Sync really is just so much better an experience right now. It's smooth, but it also doesn't lose my place in the feed every time I open a post. Trivial yet crucial!