The idea that GPT is going to make you funny is a bit like thinking you could be John Lennon if GPT would teach you how to play guitar.
GPT might help you pass off some bit of wit in an email, but any art it creates (comedy is art) is going to be circumscribed by its inability to be truly creative rather than merely copy/regurgitate existing material. And the reason art is hard is because people are extremely perceptive about what is actually creative/funny/surprising. You can’t fake it.