Since a jacket BC will hold you like a cork bobbing at the surface it may be good for new divers who are afraid of going face down in the water.
I’m comfortable in the water and realize I’am not going to drown at the surface from a few splashes.
I moved from a jacket to a Mares Pegasus back inflate. It is a minimalist approach to a BC with a crotch strap and one roll-up pouch. It trims pretty well and has enough D rings to hang props from. So while I did not move to a BP and harness it’s a nice compromise with better trim then a jacket.
I would think a new diver who is very comfortable in the water could save time and money by going with a PB to begin with, but then again many divers will never do much more then annual resort dive with rental gear.
And that’s just fine.