As solar or wind get closer to viability, it may soon come that bitcoin starts paying for massive solar investment (due to the "greedy" interests of miners buying up lots of solar capacity) and that further lowers costs of solar... and maybe wind, though I'm less confident on wind.
Replace "cryptocurrency" with any other technology service and you'll probably be left with the same net result. The datacenter is presumably charging for the co-location services, so there's certainly tax revenue and the operational jobs (as few as they are) to run the facilities that benefits Iceland.
what? it doesn't require huge upfront capital compared to say, building a factory, but risk in buying mining equipment is insane given how volatile the price/difficulty is.
...as opposed to any other business? if you're setting up any kind of business, chances are most of the capital investments won't be goods from iceland.
 other than ones centered around processing raw resources https://upload.wikimedia.org/wikipedia/commons/7/77/Iceland_...
Unless that's false, Iceland looks like it is still about as environmentally friendly as it was before agreeing to build Moonlite. Perhaps the more interesting question is what Iceland will do to meet the increase in domestic energy demand. Presumably a crude first-order response will be to increase input costs across the board by jacking up commercial electricity rates (assuming they can differentiate between retail vs. commercial facilities).