I've said that this stance is true for only this election. This is an election unlike any other in our lifetimes. As rapidly as Trump is tearing down oversight and the basic structures of government, if we allow him another four years we'll have irreparable harm come 2024.
With that being the case, Biden could be a sack of moldy potatoes and it wouldn't matter - the responsible thing to do would be to vote for him. Any other vote is irresponsible, and more likely to contribute to another four years of Trump, which would be a disaster.
In any other election, yes, the candidate who wants my vote should express why. Duh, that's the job of a candidate. This election is unique because of Trump. We've had four years to see who/what he is. Because of Trump's last four years, Biden's burden is lesser.
Of course, duh, ideally he should (and will) be courting votes.