Let's see if we can summon
@Jd Smith1 -- he's the first who comes to mind in strongly stating his preference for on-line play.
I do prefer on-line, for various excellent reasons.
The first is the sheer volume of good players available on-line. For at least two-thirds of my gaming career (started in 1979), I have have the prospect of campaigns being derailed/ruined by the loss of players without ready replacements hanging over my head. I have had to tolerate less-than-stellar players just to fill enough chairs. Since moving on line, that stress has been removed entirely.
Convenience. For the last twenty years, I had not hosted my games, as I live in the country, which meant shuttling my GM materials to various locations, a drive home after gaming, dealing with players who have poor eating or hygiene issues, or venues which are infested with rats, poorly trained pets, small children, and other vermin. Playing on-line, everything is at my fingertips, I recline in great comfort in my $1500 chair, and the instant the game ends, I am home.
Being on-line makes simple things better: instead of passing notes, you can DM a player in complete secrecy, without anyone knowing notes are bring passed. Players can be tasked to Google and post simple research questions. Handouts and props are simple to distribute, and keeping things like a stock market feature is easy.
Players don't forget their PC sheets, handouts, props, or anything else. Its always right there.
There's no question about suspicious dice or wanky rolling methods; we're all using the same dice roller.
I had used a VTT for the last decade of F2F gaming, so using Roll20 was simply a step up from the familiar (MapTool).
None of my players are getting any better-looking, so not seeing them is no hardship. In fact, I find it makes it easier to visualize role-play when I can't see the 6'3" redneck ex-biker who is playing a 5'1" Italian researcher.
There are fewer distractions; as a GM I focus on the map and the material; players who are eating mute their mikes, no one is (as far as I know) trying to force a d4 into a body orifice, there's no beating of other players with random objects for stupid moves, and so forth. It creates a cleaner, smoother, more in-depth gaming experience. In a fart-free environment.
There's no need to stop for smoke breaks, because everyone is at home.
There is, so far as I am concerned, literally no downside to on-line gaming.