I have not used a totally block chain based VPN service (but I'll be looking up those two later). I've paid for VPN subscription using Bitcoin, but that was in a service that also allows fiat payment.

Both the blockchain and VPN are both privacy centered and gives a bit of autonomy to the users. Merging both services is a venture that could take off if done right. Users would not have to reveal their identity to the VPN providers in order to use the service.