What meaningful differences do you think there are between having a privacy app like Railgun vs making privacy a "native" feature at the consensus layer of the chain?

This weakness of the account model can be mitigated by using a PQ signature algorithm in the L2. PQ signatures tend to be relatively large in size but with a ZKP L2 we can aggregate these signatures into a single PQ ZKP (e.g. STARK) so that the L1 footprint is no larger than it otherwise would be.

I work for Alpen but was not an author on this paper.

Good comments, thanks for the feedback!