> what extent these hybrid solutions retain the advantages of blockchain and to what extent they give them up
Security guarantees don't change, zk-proof will guarantee that your transaction was processed as is (without modifications). The resiliency of a rollup would depend on how it's off-chain "backend" is implemented - if it has good load-balancing, if it is multi-cloud etc.
It's possible that a specific rollup can try to censor your transaction (similar to Visa or Mastercard).
I can see a future where if a specific rollup cannot accept your transaction, your wallet would retry successfully with another rollup or try a censorship-resistant channel to push your transaction through.
Transaction fees being negligible simplify the UX for user, they may not even know there was any problem unless they look.
I don't know much about Bitcoin L2 networks, but it makes sense that lots of infra/business logic around that would be implemented by centralized companies (Square, Stripe?). No smart contracts support is a limiting factor.
Security guarantees don't change, zk-proof will guarantee that your transaction was processed as is (without modifications). The resiliency of a rollup would depend on how it's off-chain "backend" is implemented - if it has good load-balancing, if it is multi-cloud etc.
It's possible that a specific rollup can try to censor your transaction (similar to Visa or Mastercard).
I can see a future where if a specific rollup cannot accept your transaction, your wallet would retry successfully with another rollup or try a censorship-resistant channel to push your transaction through.
Transaction fees being negligible simplify the UX for user, they may not even know there was any problem unless they look.
This is a good post (somewhat technical) on rollups in Ethereum ecosystem and the areas for improvements: https://vitalik.ca/general/2021/12/06/endgame.html
I don't know much about Bitcoin L2 networks, but it makes sense that lots of infra/business logic around that would be implemented by centralized companies (Square, Stripe?). No smart contracts support is a limiting factor.