The feature that Liftoff has is automatic redirects. So for example if I am lemmy.one user and want to subscribe to !memes@lemmy.ml, clicking the Subscribe button on the Liftoff app will offer to redirect me to lemmy.one/c/memes@lemmy.ml. On the web interface, you would have to manually go to that domain.

Also all the links in my comment automatically open in the Liftoff app.