Biden's answers will be far more enjoyable. You know that sooner or later, President Trump will goad Biden into a tantrum.
When Biden gets flustered, floundering around for an answer and then try to laugh it off by saying his time is almost up, President Trump needs to quickly respond that he'll give Joe his time to finish his answer. After the panic, Biden's temper will probably erupt.
That would be too perfect. It would make Biden look like the dufus that he is and it would allow Trump to show his stateman side.