Let us briefly count the pointless of it all:
Bloomberg is a very long shot to win, but he will absolutely drain votes from the other centrist candidates, cannibalizing support for Biden, Buttigieg, and Klobucher.
This will be of immeasurable help to Bernie and Warren, the candidates Bloomberg seems to be concerned about.
The entry of another billionaire is exactly the wrong optics in a cycle where Democrats are focused on income inequality and the unfair distribution of wealth.
Making a billionaire the face of moderate Democratic politics will also be a huge boon to Bernie and Warren.