His arguments aren't exactly solid. They are:
- It isn't widely used. Well, just because something isn't popular doesn't mean it's bad. See Linux, Tor, ...
- It is only being used for speculation and criminal activity. That's simply guilt by association. I've actually seen places that have stickers that say they accept Monero, for instance. I doubt they would have put up those stickers if there weren't people who actually used that as a form of payment.
- Everyone who disagrees with this is in a cult. I don't think I have to elaborate on this one.
We badly need a payment solution that offers privacy. Even cash is getting less and less private with automated serial number readers. If Crypto offers a perspective to fix that problem, I'm all for it, at least as a concept (minus a lot of the crap that's being done with crypto nowadays).