There is a market for drugs, child porn, assassination too. Or for email spam, hacked accounts, stolen credit cards, money laundering.
If your conception of value to society is as simple as "people pay money for it", maybe you should reconsider what value means outside of a purely monetary lens.
So far, bitcoin is a much costlier way to transact compared to standard methods - both to the end user, and in terms of energy/resource costs of miners vs. a VISA server.
It probably has some value in a scenario where the government is an adversary. But the government can regulate and track Bitcoin just as well as dollars if they wish to, like they already do in the US by requiring BTC exchanges to collect users identity proofs.
The arguments about how bitcoin is the next big thing and we'll all look silly for laughing at it now are basically empty. I'm sure i will feel silly if it takes off somehow, but that tells me nothing about if/why it will take off. I'll look silly for laughing at ghosts or leprechauns if they turn out to be real too, so what?
