Devil May Cry 3: Special Edition on Switch includes a handful of new features, one of which is the ability to switch combat styles on the fly. In an interview with USGamer, Capcom's Matt Walker talks about why this feature found its way into the Switch port.
...it's mostly by design that you couldn't switch styles on the fly in DMC 3. While there are certainly hardcore players who are amazing at the game, Itsuno-san felt that you needed to ease players into the concept. In DMC 4 they added that ability to change on the fly for the first time, but part of the reason you play as Dante later, both in that game and in DMC 5, is so that a player can first ease themselves into the combat and gameplay of the game as Nero, and then have access to Dante with his dizzying array of options after you have your bearings.
Hopefully, with DMC 3: SE on Switch, we've struck a balance by making Free Style Mode an option at the beginning. People who aren't accustomed to these kinds of action games can start off in Classic Mode, and then players can choose Free Style Mode to give themselves a new way to enjoy the game once they're comfortable with the gameplay.