How do you know that? And even if it was true, what is the underlying point? I don't see the "hardly anybody uses Monero for anything other than crime (right now)" -> "cryptocurrency is useless" argument working.
The point is people have a right to financial privacy and cryptocurrencies are one possible way of achieving this. Therefore, cryptocurrencies are not a priori useless.
I'm not even talking about Monero or the particularities of its current dominant usage as I think this is irrelevant for the above point.