Seriously, if you are in front of people answering questions, having an earpiece through which someone is talking to you is normally very distracting. You have to be pretty sharp to be able to engage the audience while someone is giving you tips and such at the same time. Maybe someone would only do that for Biden when the attention is on Trump and he's speaking, but still, for someone who's losing their grip on reality as Biden is, it could do more harm than good.

Not that I'd put it past the Dems to do it anyway. Of course he was caught doing that already in a non-debate setting.