Back around 2013, I scrounged some BTC and other alt coins on forums and chat rooms and in other weird ways. Made good trading them, in terms of more crypto coins.
I still think the whole thing is a ponzi; a slow append-only database is the solution to no interesting problem. Real fraud happens by putting bad data into the ledger, not by altering the ledger.
Anyway: fast forward ten years, and prices are way up beyond anything I thought was possible. Made a good 3-4 BTC trading Vanillacoin (later VCash) until the dev went nuts and killed off his own coin. Got out with a decent profit still.
Just sold the BTC for enough for a down payment a nice electric car.
Unfortunately, the whole market just took a **** today as I decided to sell. I had a stop/limit order open, so once it crossed my threshold for loss, it sold, and everything is ok.
Still have some ETH I'll probably sell to cover the capital gains tax on the BTC, and still holding a few thousand $ worth of Doge.
Given the crazy volatility, I still do not recommend this stuff as an "investment" to anyone other than gamblers. My cost basis was literally zero (except some opportunity cost of time), so I made out. But I was lucky my coins were never on an exchange that closed.
In around 2017 when I sold a little BTC to buy my wife an iPhone X, that went through QuadrigaCX, which is now defunct. My coins were only there a day or so. But the CEO who was the only one with the password to the cold wallet "died in Italy" (or something) later and disappeared. They sent me the cash in an envelope, in the post with no tracking or anything. It was $800 short. I called, they put me on hold, came back and said, "Yeah, it was a trainee who filled your order. The rest is on its way." And I got another plain post envelope with more cash.
Take care out there everyone.