It plays basically the same role as Vaporeon, a specially defensive and a specially attacking Pokémon. Florges has a higher base stat total, and it does the job of a special defender better than Vaporeon.
Florges was also gifted the Fairy typing, and you could switch into a dragon type move targeting Garchomp or Salamence. Metagross can switch into a Poison or Steel type attack coming towards it.
Vaporeon has probably less of a use on the team, as Incinaroar usually has Brick Break for Rock types and Mienshao will usually have fighting STAB. Salamence could take care of Ground types since it’s immune. As for the fire types Vaporeon also covers, a Ground type STAB from Garchomp would take care of most Fire Types.
Moveset wise, they both usually run bulky sets such as the moves Toxic, Protect, and Wish, along with STAB and coverage. Vaporeon usually Ice Beam and Scald/Any Other Strong Special Water move and Florges running Moonblast and Energy Ball/Petal Dance.
In my opinion, Florges work better with your team, and it gets the job done well. Of course, Vaporeon is also awesome, so it’s really your decision. Hope this helped!!! :)