https://www.gizmodo.com.au/2017/08/how-exactly-do-you-get-rich-of-the-hot-new-cryptocurrency/
"For the uninitiated, mining for currencies like Bitcoin and Ether means devoting a huge amount of computer processing power to doing accounting sums for the platforms behind them, helping to verify the accuracy of the public blockchain ledgers.
You're essentially getting rewarded for keeping the books for these platforms, which we've explained in more detail here, and the rise of cryptocurrencies like Bitcoin and others has led to a flood of amateur enthusiasts jumping into the mining business — the idea of having your computer whirring away making you free money sounds almost too good to be true.
And in reality, it almost is — you can get rich from cryptocurrencies, but you need to put in plenty of work, and have luck on your side. You're more likely to get a windfall due to market pressures than the quality of your mining rig, which is why it's only worth a shot for the most committed and the most adventurous."