Vitalik Buterin said a multisig approach lowers the risk of catastrophic failure during the early years of Stage 2 deployments

Quotes that support claims

In his discussion, Buterin further explained that another key consideration is the quality of the underlying proof system. Vitalik Buterin has suggested a smarter approach for securing Ethereum rollups. Instead of sticking to a single proof system, he proposes using a multisig setup with several independent proof systems. This will lower the chances of a complete failure, especially during the early years of Stage 2.

Additionally, note that the probability of the proof system breaking can be reduced greatly by making the proof system itself a multisig of multiple independent systems (this is what I advocate in https://ethereum-magicians.org/t/a-simple-l2-security-and-finalization-roadmap/23309 ). I suspect all stage 2 deployments for the first years will be like this.