Least surprising announcement of the year!
Despite pundit speculation to the contrary, it was always obvious Biden intended to run, unless catastrophic health problems and/or a major scandal prevented it. I have a long list of objections to Biden's policies, and I think it's irresponsible for him to run at his age, given the significant likelihood of age-related cognitive decline occurring (he will turn 82 in 2024). The Democratic Party should be able to produce a candidate who is younger than Biden, at least as competent, at least as electable, and no worse on policy. These aren't such high standards! But Marianne Williamson and RFK, Jr (Biden's only likely competitors for the nomination) don't meet them.
That said, on both policy and competence, Biden's still a lesser evil compared to the most likely GOP nominee - Trump. Whether he's better than DeSantis (Trump's leading GOP rival) is a more complicated question. But what I've seen of DeSantis's recent agenda does not inspire confidence, to put it mildly. He seems to be pushing a kind of "Trumpism without Trump." We'll have to see if that trend continues and/or some other possibly better GOP candidate gains momentum.
And if you're into really shitty presidential candidates, this time around the Mises Caucus-dominated Libertarian Party is likely to nominate someone truly horrendous, as well (assuming they don't just implode completely).