DeSantis voters look a lot like Trump voters. In fact, they're pretty much indistinguishable, since DeSantis was using the same talking points as Trump, only more coherently (and effectively in Florida). Haley voters look more like traditional Republicans, who are people that really don't like Trump. Right now, assuming that both Trump and Biden are the respective nominees, at least some Haley voters will move to Biden rather than voting for Trump. If you want to keep democracy going, that's a good thing. E.g., you may not agree with Biden on every thing, or most things, but you agree that he's not going do his level best to be an autocrat.
The MAGA bullshit is popular enough that Biden needs to either be able to mobilize far, far more young voters than has been done in prior years, or peel off some moderate Republicans. The latter is likely more politically feasible than the former.