Every currency is quotes in terms of other currencies to allow for exchange. We even quote gold in terms of FIAT currencies for exchange purposes. It keeps me from having to pack up oz. of gold and shipping it to you.

I think Bitcoin as well as some others will survive for good reasons.

Bitcoin because it was the first mover and adopted by a "black market". As long as they are willing to use it a measure of exchange of goods and services it will survive.

Steem or SBD survives because it is earned by value added work. These blog post are the product of someones efforts and brains that ads value to someone else. So it is a innovative way to measure effort and then assign value to that effort based on the benefits someone else get from that effort.

Ripple (XRP - Google backed crypto) survives because it offers real value in making the financial markets more efficient. Transfer dollars is generally inefficient as a ledger between banks. They could use gold, that is even harder because of its physical nature. So , at least ideally, something like ripple is fast and can be a proxy for value (as long as you can eventually convert to other forms of currency). Plus organizations like American Express (plus others) are experimenting with it for its intended use. As they become more confident it will grow in value.

These are the kind of things that I look for when researching crypto. Is there a real benefit to someone somewhere. It has to be more than just another currency created by automated systems without real cost.