Not true. There are enough places where you can buy BTC for cash. In Austria, you can buy at gas stations or in the post office. As long as you use a fresh wallet and only one time, I don't see who this could identify you. It may be backtracked to Austria, of which I am not a citizen.
Bitcoin are non fungible and by design traceable. Anybody can figure out where they came from and gas station and post office have security cameras. Use the right tool for the job which is monero.
There main slogan is "Fast, Secure & Anonymous VPN"
meanwhile they require name and email unlike Mullvad which pioneered the concept of random account IDs for login years ago.
>If in doubt, pay with Bitcoin and use TOR to connect to your VPN.
Bitcoin is not and never will be private or anonymous. Use monero or cash.