It is true that Einstein was wrong about his insistence that there must be hidden variables, but I'm not so sure I would call him on the wrong side of the debat

It is true that Einstein was wrong about his insistence that there must be hidden variables, but I'm not so sure I would call him on the wrong side of the debate, as the correct hypothesis wasn't available during his lifetime. I wonder what he would have done with it had he heard about it. Einstein's objection to spooky action at a distance and clinging to determinism is exactly the kind of thing to point to when trying to explain his amazingly good intuition for the character of physical law. He was 100% right about the action at a distance not being real and physics being deterministic. To be clear, entanglement is real, but there's no effect that happens at faster than lightspeed; the resolution to this is, of course, MWI. As for what use there is - the primary use is that we can all stop being confused about this. And stop thinking that just because quantum physics is mysterious, it must necessarily be connected to other concepts that are mysterious too, like consciousness. And when else would we question the justification for learning the truth of what we all and the universe are made of? (P.S. In what sense do you believe that MWI is very-weak determinism? It's deterministic through and through.)