Well, this has the makings of a disaster.
Democrats must be wishing that Biden will eventually decide not to run, and Harris will agree to be dumped to the sidelines. The one possible benefit of Biden/Harris running again is that they would probably avoid a contentious primary season, while the Republican primaries are likely to be a brutal bloodbath. Their hope is that the GOP fractures and whichever of Trump or DeSantis wins will lose too much support as voters stay home in protest. But this is counting on Biden being able to handle the rigor of a campaign, and I just don't think he is up to it.
I do wonder if they'll make Kamala Harris step aside and find someone else to run as Biden's VP, with the understanding that they will be there to fill in when Biden is finally determined to be unfit to complete his term. If anything scares voters more than an aging Biden or Trump, it's the thought of President Harris.