Yoga Shoes?

Got an advert that yoga shoes are on sale...wait, you need special shoes for yoga?

I have gone to one yoga class (I probably should do more), and everyone was barefoot, now you need yoga shoes? Is this just purely a marketing thing? Someone's new way to make millions?

I appreciate the yoga pants trend, really I do. So now everyone will all be wearing yoga shoes to the local coffee shop to get their spiced hot chai latte. 

Will Nike release an Air Guru? Adidas, a Climiguru? Will you need a special sock to wear with the yoga shoes? Will there be special shoes made for pronators and supinators? A special instep grip for cobra? Will you need different soles depending on the yoga mat you use? Maybe some quick drying ones with an anti-microbe lining for use in hot yoga...

I wish I had thought of this...