It would be unnecessary if Lemmy's web UI was actually reasonable. As it is, every single time I open the app, I have to log in again, then refresh the page to see anything at all. The news feed is paginated rather than endless scroll. When I press the back button on a comment thread, it takes me back to the page before the one I was looking at, so I lose my place. It's borderline unusable.
So I guess I'll give my ad eyeballs to the app that actually works.