Reason being, Biden will be able to speak (even with stutters and stammers) but coherently the job they have done for the last 4 years and what is to come for the next. He will respectfully explain how the United States doesn't need a criminal as the next POTUS, who still has never admitted that Biden beat him like a drum in 2020.
This will enrage Trump who will be prepared to give a rally type response, but he'll become unhinged trying to reply to Biden.