I tried watching Billions but I couldn't get into it. The characters are not at all sympathetic, eg Damian Lewis' performance seemed to be based on pre-politics Trump. I might try it again at some point, it seems like a well done show.
I think you're right, a show like Veep takes shots at the political system, incompetence so you don't end up hating the characters like you would in real life, or in a drama. There are a lot of comedy characters who are narcissistic and uncaring who would be villains if they were played straight.
Plus of course good comedy characters/actors are generally charming and likeable.