I mostly use Bitcoin to buy things that I either don't want on my credit card bill or from merchants that I don't feel comfortable trusting with my credit card information.

For me, that's generally things like gift cards, VPN and VPS rentals, etc. It also seems to be gaining significant traction on porn sites, both for memberships and for per-artifact transactions. I expect that it will continue to be useful in the case of memberships in particular because you can't set up a recurring payment in Bitcoin, which protects the purchaser from being unexpectedly charged later.

> I don't think I've ever seen one that accepted Monero or Ethereum. Maybe Litecoin a few years back.

I agree here. Although I've seen a few, they're all very much amateur sites run by other crypto nerds, so they don't really count.

That said, I don't think that matters so much anymore. Sites like shapeshift.io have made it nearly effortless to move between cryptos, so if you want to hold and transact with friends using Monero and buy things using Bitcoin, there's much less friction than there was a year ago.

> So if it's not buying stuff, what use cases do you have in mind?

In my view, here are the main use cases for Bitcoin:

1) As a currency/"digital cash". There are definitely use cases (see above) where Bitcoin is a superior currency. There are also instances where people cannot transact using the "normal" financial system, and Bitcoin gives them the ability to purchase things online. Examples include minors and citizens of states without great access to the world financial network.

2) To evade state control. I've personally got a friend in Venezuela that I occasionally send some Bitcoin to help with family matters. Their currency is literally worth less than WoW gold at this point, and the state controls the dollar:bolivare exchange rate. I'm able to send him $50 in Bitcoin and he's able to exchange it for food and medicine, or for bolivares at a rate many times better than the "official" rate. Likewise, it seems that the Chinese are using Bitcoin (and other cryptos) to evade capital controls and get their assets out of China.

3) As an investment. The long-term deflationary nature of Bitcoin means that it's an excellent place to keep "disposable savings" - so long as you believe in the future of the currency.

4) Complex but bulletproof financial planning. My cold wallet is set up using m-of-n. There are several private keys out there to it: I have one at home in my safe, one in my head, one on a Yubikey on my keychain, my wife has one, my attorney has one, my parents have one. Three of those six keys are required to sign a transaction for it to be valid. That means that no one individual, other than me, with access to those funds can spend them on their own. If I die unexpectedly, my wife can spend them. If we both die unexpectedly, my parents can spend them. If somehow I, my wife, and my parents all die unexpectedly in very short order, the funds can still be recovered by the executor of my estate. This sort of arrangement cannot be made in the traditional financial system without exposure to litigation risk.

Another place it would make sense is in a corporation with strong spending controls. A wallet where the CEO, CFO, and CSO all must sign off on a transaction is totally possible. That wallet is then 100% guaranteed not to ever be spendable by anyone outside of official channels. There is also a public record of who signed each transaction and when for audit purposes

5) Asset verification. Do you know, for sure, how much gold is in Fort Knox? Of course not, we must simply trust that the US government isn't lying when they state the size of their reserves. With Bitcoin, if an organization has 20,000 BTC sitting in a wallet, they can sign a message to that effect with the private key that corresponds to it. That signature can then be verified by anyone, and we can be confident that they do in fact control the coins at that address.