I get what you mean - they're good at playing themselves or a caricature of themselves experiencing the range of emotions.
Like they can't play a character wildly different from themselves but they can adapt their personality to a character's role pretty well. Like Kevin Hart probably couldn't pull off a character like say John Q well but he can play "Kevin Hart if he was a widower and a single father working a desk job" great.
A lot of comedians do dramatic roles well. Weird, but it isn't at the same time.