Because they're liquid with bitcoin they're effectively liquid with all the other currencies in the world, including each other. So you can do things like gauge the profitability of a given altcoin with code and switch your mining based on the current highest daily return, and you can do things like run trade bots that trade into and out of bitcoin and that altcoin depending on various market indicators etc to get the best return on top of that base return, and last of all you can do the same trading strategies with bitcoin and fiat currencies themselves, so it becomes a three layered freelance trading strategy.
To summarise;
* Miners pull down altcoins with raw GPU horsepower.
* Bots trade between the altcoins and bitcoin on market indicators that work best.
* Other bots trade between bitcoins and fiat on market indicators that work best.
I used to just be a coder working for employers directly but this makes me accountable to nobody but the effectiveness of my algorithms. I'm still open to the freelancing side and looking at other opportunities because it is largely passive, but it's the first opportunity I've ever had where I become completely unaccountable to other human beings, and I must admit that has a lot of attraction to me.
I'm a global roaming digital nomad and have been for the past five years or so, but I have always had to worry about being contactable by my clients and timezone shifts and things of this nature, now that doesn't matter so much as I don't even need to talk to anyone at all if I don't want to. After finally achieving absolute complete communication disconnection with the entire rest of humanity though I am starting to feel the slightest inkling of what I have constantly heard other people talking about with feeling something missing in not being in the office and interacting with others all the time.
It's a crazy world, and I'm a crazy person.