or any other currency? if you have free electrcity (please dont ignore)
Simple. It means that mining hw which would normally have a negative profit for those who pay for electricity, are profitable. This added mining power decreases the profitability of the other miners, and the market reaches equilibrium, as this is the only thing a market can do.
For one thing, it still isn't free. You need equipment and must invest time. There is a cost to such things.
However, now that I've answered the obvious, I will now take a moment to be a dick and tell you that if this isn't as obvious as 2+2 you should probably stick to participating in the consumer side of the economy.
