Bitcoin is a risky thing to invest in, but it can be very rewarding. I recommend you buying a fraction of a bitcoin (rather than the whole thing), if you really want to. You dont have to spend the whole 13k. As for bitcoin mining, unless you have a powerful, dedicated gpu that you want to use, theres no point. You would  lose money just using your everyday PC because of electrical bills and gpu aging.

For what @palmerageddon said, all currency only contains the value that people put in it. People could start valuing pmc money, and make it equal to the euro for example, and that would be perfectly legit. We could buy a car with it, if both the producer and consumer agree on its value.

Think about it, ig money on the server only has value because of the people who play.