So there is still the PoW cost but how do the PoB blocks then contribute to the consensus?
How would an attacker with 51% of the PoW fair against defenders with various levels of burned stake?
I'm not too clear, but I don't think PoB can help defend against PoW 51% attacks. PoB does increase trust score of a chain for resolving forks but might not kick in in time for double-spend attacks?