You buy a few balls (or earn them on Steemit), shoot them into the machine... and hope you get more balls in return. Gambling is illegal in Japan, but it's basically a loophole around the law. You can cash your balls in for prizes.
Consider pulling a few balls out of the machine while you still can. Crypto ain't going to zero, but mortgaging your house to buy crypto is a stupid ass idea. The on/off ramps to the cryptoworld are shut off right now, so consider taking gains when you can, and remember this crash as an example of when times are tough.
Crypto is worth little to zero... if you can't buy it and sell it. Doubly so with ultra-high transaction fees.