Crypto coins are no more a currency than baseball cards, both are backed by nothing but speculation.
Don't confuse speculation with tangible backing.
Speculation is what drives the price relative to other currencies.
The "backing" is based on people's trust in the thing, in which it is essentially no different to US dollar currency, or even gold to a large extent.
Don't forget, there are quite a few crypto currencies with actual purpose beyond just being "worth something" (and Bitcoin isn't one of them).
Look at Ethereum and IOTA for example, they have the ability to create smart contracts not to mention ETH is far quicker to transact than Bitcoin is (minutes vs. tens of minutes).
Ripple is another, it's able to perform transactions within seconds at a rate of thousands per second, that's up there with the big credit card companies. In fact Ripple has already been adopted by a lot of big companies with some of the big banks in Australia trialling the technology, I believe even American Express are on-board. It's essentially aiming to be a replacement for SWIFT. Rather than taking days or weeks to transfer money, it's done in seconds at fractions of a cent, the cost
savings alone are enormous.
Comparing crypto currencies is like comparing apples to capacitors.
One fact remains, crypto is here to stay whether you like it or not. It won't replace traditional, government-backed currency any time soon, but rather live alongside it. As long as you can convert any kind of crypto into money, it's worth something.