Can you elaborate on this?
From my perspective, SSF helps ePBS achieve a better honest builder payment safety property: if the auction-winning builder is honest, then that builder’s block must become canonical. In fact, an SSF protocol can quickly (i) identify the auction-winning builder from the proposer’s messages (potentially multiple equivocations), and (ii) finalize the auction-winning builder’s block. We cannot achieve a property this strong without SSF because all blocks must go through a long unfinalized period, during which they bear the risk of getting reorged.