Desantis is somewhat of a slick politician type, but he's the best the Republicans have, and he really scares the Democratic Party.
He's young (born 1978), doesn't have a lot of baggage, good at pushing hard on issues where conservatives poll well with swing voters, and has a similar appeal to the working class as Trump did. At the same time, he doesn't have the flaws Trump carries, such as saying/tweeting stupid things, or having a shady past.
If you take Trump the politician and clean him up into a more polished and younger package, that's Desantis.
I generally like him. The whole slick politician vibe doesn't resonate with me very well, but all in all I think I'd be happy with Desantis as both a candidate and a President. Mitt Romney, for example, is someone I would have liked as President, but I never thought he was a good candidate.
Desantis running would also lock up Florida for the GOP, which has been happening anyway lately (even in 2020 when they lost), but it's still a swing state, and still nice to lock up those electoral votes which are now the 3rd most in the nation (ahead of New York!)
Texas/Florida now make up 70 total EVs, which almost negates the guaranteed 82 EVs from NY/CA going to the Dems.