Anything that can store value can also be used for transactions. Bitcoin fits this description, and like money, or any other value storing object, it’s mostly about the perception of value, but also how transaction-oriented the thing is…
They say bitcoin is backed by money, US dollars or whatever, but the truth is that bitcoin is backed by computers. Without computers there is no working bitcoin. Yes, bitcoin is decentralized, so if one or more nodes fail, the system is not fucked. However, it assumes all nodes are equal. Latency is minimal, non-existent.
Will the many cryptocurrencies co-exist like the many credit cards out there? It does seem that concurrency (haha) is not a problem. People will be forced to trust this type of currency at some point, the gradual shift, with bumpkin types the last to adhere, given elites and billionaires continue to invest, seeking more fortune.