Most currencies have no real "substance" or "value". They aren't backed by anything except the promise of the issueing country that they are indeed worth something. The government of the issuing country controls the amount and relative worth of thee currency by printing more of it or taking it out of circulation. The main allure of bitcoin / crypto is it takes that control out of the government's hand (unless it is outright banned by a country). It also levels the worth of different currencies. One bitcoin is worth one bitcoin no matter what country you are buying or selling something in.
I wouldn't by any means put a large chunk of my networth in it. But then I wouldn't but a large chunk of my networth in one investment ever.
if the bubble does burst in crypto, there will still be millions and millions of people who made money. For every buyer there has to be a seller. If you buy some and it doubles or triples and you sell the amount you orginally invested and let the rest "ride" then you wouldn't have lost anything at all.
It's not for everyone. It is HIGHLY speculative. But as others have pointed out, we are already at the point that you can complete transactions for a variety of different products and services in bitcoint / crypto. It's no longer the future. It's here. It's happending NOW. It's just a matter of if governments allow it to conitnue and compete with their fiat currencies and if it's popularity and use continues to be adopted by more and more users.