Hi, Damian here from Composable Security. We support this proposal.
We have seen multiple issues around deposit front-running and even reported vulnerabilities through BB in specifically touching this class of attacks. So while it’s quite old, it is definitely still relevant.
Also, even within a single protocol there are different approaches to this problem depending on the trust assumptions around operators, the staking path, or other operational constraints. Having a protocol-level mechanism for binding withdrawal credentials to a validator key should simplify deposit handling across those different paths.