There are various opportunities to make money online beyond the cryptocurrency world by offering various services or designing products and similar things, but they all have one thing in common: Because they work with fiat or standard currency, working with these websites tends to be more fiddly, both for the user and for the company itself. There are various hoops everyone has to jump through to make it all work.
Cryptocurrency simplifies things. The company or service has to acquire the cryptocurrency it wants to use for payments and the user has to get the right sort of crypto wallet but other than that there are really no hoops to jump through. The user can provide whatever service or do whatever work they wish and get paid directly, and often much more quickly, with crypto.
If at some point that person wants to sell their crypto for fiat there may be some hoops there, but there are still ways they can spend their crypto to make even that easier, whether it’s finding a website that accepts the crypto directly as payment or by using the crypto to buy gift cards which they can then use to buy whatever they’d like from the appropriate store.
All in all when a website offers crypto as payment it greatly simplifies and streamlines the whole process.