I started out with a 40 sized glow powered trainer about eight years ago.
I have flown lots of different planes since then, and I still like to have a trainer plane on hand.
Moral of the story .... if the Super Cub survives keep it and fly it .... you will certainly become capable of flying more advanced models, but there is no reason not to hang onto and fly the Super Cub.
Depending on which direction you go with the model airplanes you may have more opportunity to fly the Super Cub than your faster more advanced models.