I don't, and I think part of why it's not used so much for transactions is privacy. Most cryptocurrencies provide a public log of all transactions.

Bitcoin Private https://btcprivate.org/whitepaper.pdf will add privacy, we'll see how it goes. Also LiteCoin is introducing LitePay in a few days, which might change things.

NewYorkCoin https://www.wsj.com/articles/newyorkcoin-gains-traction-in-c... is actually used as currency in NYC, and is fast enough and has no transaction fees.

So we're at the early stages of things, but between Bitcoin Private, Litecoin, and NYCoin, I expect lots more people will be buying with cryptocurrencies over the course of 2018