Personally, I'm not into a single point of failure device. Same reason why I eschew paying with a cell phone. More convenient? Sure. But lose your cell phone and you have a lot of things to account for, doubly so if you have no form of remote wiping it.
A wallet is a single point of failure device. It's a lot more of a hassle to remotely wipe my wallet (remember all the cards, cancel them all individually).
Not to mention the fact that now one service has all of my cards and their information? Coin better know what they're getting into. I'd prefer the hassle of many sites than one with everything, just not worth it to me.