genuine q: any tips on where I can read the best explanation for why user's shouldn't be concerned about the lack of fraud proofs on optimism? cc

yes, I'm no expert here but that is the part that is currently disabled.

yes, I'm no expert here but that is the part that is currently disabled. https://community.optimism.io/docs/protocol/#next-gen-fault-proofs

Has nothing to do with the sequencer. It just means that anything the proposer says, goes. With arbitrum (until BOLD launches very soon) only a permissioned set of challengers are allowed.

Robust, permissionless fault proofs and slow upgrades are essential, otherwise you just trust the rollup devs with all your funds.