In practice, rollups can offer better finality than ethereum's base layer by using a bonding scheme. Basically, a rollup provider can sign a message that says "

In practice, rollups can offer better finality than ethereum's base layer by using a bonding scheme. Basically, a rollup provider can sign a message that says "I promise that this transaction will become finalized, otherwise I forfeit my bond." Depending on the implementation, the receipt of that message can give the payment recipient pretty good confidence that the transaction will be finalized. I believe some rollup providers are either doing this already or currently researching it.