You're not really mistaken. You can do some interesting things with eggs--very precisely control the texture of both the white and the yolk (which relates to the coagulation of different proteins). But, for the most part, I use sous vide for meat and, especially, red meat. I'm not sure I'd say you need to eat a "lot" of meat (it's not like I use my sous vide setup every few days) but it is primarily for meat.
I must say that I've never tried it with chicken thighs. I do use it with boneless breasts now and then for when I want some cooked chicken for a salad or noodle dish. It really helps keep the meat nice and moist while being cooked just right.
