Bert Hubert has an interesting idea about the reasons for interons. He explains this in his talk 'DNA: More Greatest Hits (SHA2017)' The interesting bit, with some introduction, starts at: https://youtu.be/rCdhsN--Mdo?t=1440

This is a follow-up talk to his talk: 'DNA: The Code of Life' https://www.youtube.com/watch?v=EcGM_cNzQmE