McAfee charges $105,000 for a single tweet about your coin. His followers blindly lap it up. He is orchestrating a massive pump and dump and getting paid for it.
He is fully aware he will never get elected - he is likely just going to use the platform/publicity to further increase his pump and dump scams and get richer from idiots that believe him.
Basically this. I think he did run in 2016 though or had some debates back then so it isn't a 100% a farce. But I do think he is leveraging his position with his following to use that in order to make him some money. Whether he runs in 2020 well we have to wait another year to see that.