I've added Bitcoin payments to all of my ecommerce sites. Bitcoin is a great way to transfer money from person to person while sticking it to the CC companies (aka processing fees). When you get your money, it is yours. Currently there is no chargeback mechanism so this is appealing for merchants that deal with fraud a lot. I don't think Cryptocurrencies are going away, Bitcoin might eventually, but I doubt it.
There is some confusion how merchant payments work with bitcoin. I use coinbase, when someone reaches checkout Coinbase has the exchange rate from BTC -> USD already calculated for that point in time. The customer is prompted to send X amount of BTC to my coinbase wallet. When the transfer is verified Coinbase immediately converts the BTC to USD in my account. Basically you aren't left holding BTC if you don't want to. BTC is just the way the money changed hands.