I personally do not think you have to keep a snake only for the "challange" and some sort of silly thought about how it could hurt you. I feel that is a really small side of herping and frnakly, I don't care how much a snake takes to work with. If I like the species, I don't worry about what humans think.
I keep colubrids because I am interested in them. I don't like 10 foot pythons, I have no interest in them. If someone was to say to me "Ohh!! But you have no challange working with them, it takes no skill!" Well I say so what? This isn't about ME and how "cool" I am or how experienced I am. Its about what type of species will keep my attention, and will help me learn more about snakes in general and its species.
Tell your friend to learn more about all snakes in general, and research them, and soon a favorite will emerge. And don't worry if its not the hardest thing in the world to keep or not.
P.S UM yeah no. I am not trying to start any arguements here. I just think that all snakes have value as eucation animals and pets.