This solves the problem of slow transport between your frontend and your backend, but it will still incur a lot of unnecessary load on the database as well as compute on your backend (which isn't normally a problem unless you're using something really slow like Rails).

Why? Queries would still have to be done. Yes, a few things would be duplicated (authentication), but on the other hand, queries can be cached at a more fine grained level. It's easier to cache 3 separate queries of which one can be re-used later, than to cache one monster query. s/query/response