Look, I will give you just one example. Look at the mess with the Ashley Madison. Imagine if their users had an opportunity to pay in Bitcoin by staying anonymous or even semi-anonymous. I am sure many of them would choose this option.
Bitcoin can have many use cases like this one in the adult and porn industry, meeting and dating websites, etc. And I am sure it will have after the Ashley hack.
True, keeping outdated services like credit cards where they have to store all of the people's data in a server (that WILL get eventually hacked exposing to millions of people and losing tons of money) it's really stupid. Bitcoin is superior in every single way. Same for cam websites.
Not sure about escorts tho. A escort might still be safer with cash because it doesn't have a public ledger... that's why we need stuff like confidential transaction, and higher anonymity by default. Bitcoin is not fungible enough for someone like a escort to see it as better than cash.