It's fairly important

I'm a bit leary of the idea of putting a hard cap on age; there are older senators the same age as Biden (Bernie Sanders comes to mind) who are in better shape than him, and past examples as well (see John McCain). I don't think he has dementia and my position on it is that until we get more information, I'm not going to put my foot in my mouth. What is clear is that he very much looks and feels 82. Trump is old too, don't get me wrong, but even if the story being floated around by Biden's aides is correct (and I'm inclined to believe it is, as it would do a better job of explaining his better public appearances in the midst of this), it does raise serious concerns about whether he will be governing should he be re-elected, and more importantly, whether he can run a vigorous, effective campaign given his precarious position in the polls.