I used one. A friend told me that I would not need it because someone can just hold my lip gloss. But then I decided that I also wanted to have my phone, room key, and some cash on me. So, in my mind, that was enough for a purse.
I bough this clutch from a vendor on etsy.com: http://www.etsy.com/..._ttt_id_5323931. It's big enough for my phone, camera, lip gloss, room key, and some money, but still compact. The same vendor also sells that clutch with different pins/brooches on the flap, all very nice.
I really like it, but I doubt that I will ever use a white clutch again. Since I am the first of my close friends to get married, I've offered to lend it to all of them once it's their turn. If you're thinking of using a purse, I'd ask around for one to borrow. Unfortunately for me, no one had anything that worked!