...So, although they are using dodgy methods (using other people's computers), are they earning the coins legally, or stealing them? That's the bit my tech challenged brain isn't getting!
To add to the above, cryptocoins have various levels of legality as tender depending on the country. They have various taxing interpretations. They are under varying levels of financial regulation wrt/ activities like running currency trading sites where you could make futures orders or trade etherium for bitcoin or the like. One interpretation is to see them a bit like commodities futures trading, where the commodity is Dorothy Returns to Kansas someday (coin becomes legal currency in major markets).
As far as I know it is not illegal most places to run a miner, either by yourself or in a collective (it takes a lot of processing to get to a 'coin' payback, so joining a pool means faster results and you split the coin). Once you have a coin or fraction thereof, then turning it into cash may be hard or easy depending where you are. A lot of people are just sitting on what they have accumulated. And with good reason. Bitcoin a few years ago dropped to 250. Now its around 5k$. Early bitcoin mining was easier and so some people are sitting on hoards.
As mentioned, the amount of power (kilowatt-hours consumed by the computer) required to generate a coin of one or another sort can easily exceed the value of the coin. There are calculators online that can tell you given how good your mining software and hardware is, and what your local power cost is. Basically in the USA its mighty tough to break even if you get in late on a coin, and you do need to throw a couple thousand into a computer (multiple graphics cards) to really have decent processing power to be a penny-ante player.
You can work the curve by getting in on early moments of a new coin, or major crashes of a coin, and then riding it back up. On the downside of this, most of the fluctuation in coin prices is driven by speculation in Asia, so good luck with that.
The generally agreed intrinsic material (as opposed to ideological) value plain cryptocoins have, as far as I can see, is the speculation that someday they will be declared to be legal currency in major countries, and thereafter they might be somewhat immune to currency shocks since there in theory limited numbers of coins in some coin types. Some folks still hope coins of various sorts can be totally independent currencies.
Bitcoin and etherium price fluctuations have earned some folks millions they have been able to cash out, so I suppose that is real. But its the wild west, as in if someone sticks you up, ain't no sheriff gonna save you. Immune to shocks? If during a "shock" the net is up and coin activity is not shut down politically or technically, maybe.
