 Biden hasn't done a lot of one-on-one interviews during his presidency, and none of them have been as high stakes as this one. After that halting debate performance, even allies of Biden have openly questioned whether he has the cognitive function to keep doing the job of president for another four years. They want him to show that he can perform well without a teleprompter. He leans really heavily on teleprompters, sometimes even using them at fundraisers in people's living rooms.