For someone between 5'4"" and 5'9", give or take a few inches either way, The 650B (584) makes a lot of sense because the smaller wheel diameter allows you to have fenders and wider tires without compromising the frame design. Tall riders on big frames might be better off with 700c or 27" wheels. Short riders would probably be happier on 26(559) wheels.
Since this is a commuting forum, I don't think the problem of being stranded in , say Kirghizstan, would arise. Touring with 650B might be another matter.