Eh, barbarians, bards, fighters (meaning the magic subclasses) monks, rangers, rogues (magic subclasses), sorcerers, and wizards, etc. do not have any special ties or consequences to their magic powers. I don't see them as pointless classes to play.
Any of them can, and that can be fun to play, but it is certainly not the only way to enjoy playing a character.
I had a lot of fun playing a
3.5 warlock who got his powers being descended from the archdevil Fierna but being a good guy who did not work for her (in contrast to his father, my prior character who was a
tiefling soulknife who did work for her, which was also great fun to play).