Plus, Reed Richards is a genius, and there’s never really a situation where having one on hand is a bad thing.
The key will be finding the sweet spot for these guys, i.e. effective ways for them to contribute to adventures without feeling redundant.
The MCU is slowly, but surely going to get more cosmic, and when that time comes, the Fantastic Four will be the perfect candidates to get in on the action.
They probably won’t be a tremendous help to the likes of Captain Marvel, but everyone always has a part to play in an ensemble adventure.