There's many use cases.
Here's a few examples:

Bitcoin

A decentralized store of value. Some say it doesn't work because it has its bull and bear runs, but that's where the whole trick is. It's a store of value but it has moments when the market price goes down and this is the time when you shouldn't convert it to anything else. When you take a 4 years out of a bitcoin's life you'll see there were moments where it was higher and lower from the average and this lack of stability doesn't mean it can't be a store of value. 

Freedom to move your wealth around the world from one jurisdiction to another. This is something people in China and many other countries can't do freely.

A way to avoid abuse by the government like in Canada where the government was trying to curb protests by stealing the money from people's accounts and making them unable to buy food and fuel.

Great if you want to donate anonymously or buy something online without your bank knowing about it.

A way to avoid currency exchange fees and bank fees - great if you travel a lot and meet a lot of people. You can easily book a flight or a hotel with it.

Allows you to circumvent government bans and restrictions. Some countries will not allow you to gamble and block bank transfers but having cryptocurrency can help.

Gives you 24/7 access unlike banks and stock exchanges that don't work on weekends.

I recommend people have some bitcoin in case of emergency. People in Ukraine who had to get away from war had problems getting cash from their banks but packing a drive with your wallet on it and accessing it once you're in a safe zone is fast and easy.

Great conversation starter. Many people around you could be bitcoiners!

An investment opportunity that outperforms even in bear market. If you had fiat money in 2021 in Turkey and decided to buy bitcoin at 60 thousand you made a good decision. With 80% inflation their fiat currency is down much more than bitcoin and people say its bitcoin that crashed.