FWIW I'm not implying that you're not allowed to do whatever you want. I'm definitely not about the games that use always online to force you to play to the developer's publishers (cash grab) vision. Even if you "cheat" on a single player game who cares?

It just for me wouldn't be particularly enjoyable to just randomly turn my warlock into a bard to make an encounter better or whatever. I would want the bard to earn their level as a bard.