Yep, comparing SHA2-based macaroons and ED25519-based biscuits, you'll have size and computational performance advantages for macaroons as well as post-quantum

Yep, comparing SHA2-based macaroons and ED25519-based biscuits, you'll have size and computational performance advantages for macaroons as well as post-quantum resistance. But that doesn't help you if you want to solve the network performance and failure issues with verifying macaroons. There may be strategies to solve some of the biscuit disadvantages using different signature mechanisms like BLS, but that might not help with performance and will not currently get you post-quantum resistance.