Not too many years ago, there were trusted services that sold Bitcoin (and Liberty Reserve and Pecunix) for cash sent anonymously through the mail. I haven't needed that for years, but I'm pretty sure that such services still exist. And given the escrow sector that's developed to serve dark marketplaces, trust is likely far more verifiable.
Cryptocurrency and meatspace money are now entirely separate for me. I earn all the cryptocurrency that I need anonymously online. And I don't risk manifesting it as meatspace cash. While that's not currently workable for most people, I don't see why it couldn't become so.
How do you buy things in real life?
Now, most people I know who hold Bitcoin are motivated primarily by other reasons. But still, I can cut down my cash spending/donations by a few $1000/yr just by doing those things above — which have fairly loose ties to my physical person — with Bitcoin.
The point is that my online anonymous coward personas and my meatspace identity are as isolated as I can manage.
I've also done some privacy-related development. For example, a client wanted a private IKEv2 server with a nested VPN chain backend. To provide iOS devices with anonymity that was stronger than VPN services provide, but also easy to use.
