I'm not saying don't put money into Bitcoin/cryptos; I'm saying don't put in more than you would feel comfortable losing at a casino.
I don't feel comfortable losing any money at a casino, that money goes to an industry that I don't care to support; But I'd be fine losing money in crypto because It's something I want to support.
How does buying and holding Bitcoin promote a decentralized economy?
Like any artificial representation of wealth(aka currency) it's only as strong as the group of people recognizing it as a representation of value.
So by storing labor or wealth inside bitcoin, you're strengthening the network of participants, thus strengthening bitcoin, thus strengthening(or supporting) decentralized currency.