Why do you want to hide your socks when wearing loafers? Loafers are meant to be worn with socks, whereas boat shoes are meant to be worn without socks. I have many socks in multi colours to wear with loafers. In fact loafers are the only shoes that show my socks off, so I choose socks for their look as much as their fit and how comfortable they will be, with loafer wearing in mind.
Purely because it seems to be the look at the moment. I'll be wearing them mostly on foreign holidays and in the summer. I'm not into the trousers at half mast thing but I think there's something pretty cool about the sockless look with loafers and a suit.