He often wears them at his 'press conferences' even though no one is near him. Clearly to virtue signal
I think wearing one at the debate would be a terrible look, people want to be able to see the face and expressions of their potential next president
However not wearing one would enrage the covid fanatics, and the media would then have to spin why he was right to not wear one
I'd bet he will: both to appease the dem narrative, and so his staff can find an impersonator to answer questions for him offstage.