Is there any advantage to running a node in the ISS?
a.1) Particularly for the company "SpaceChain" that actually runs it, ridding piggy back PR on the name of SpaceX and the recent Tesla/Bitcoin craze.
b) Every time Elon Musk appears in a sentence together with crypto currencies, prices bounce around (exactly what you want in a currency, right). This can be used deliberately to make bank and in contrast to the stock market, there is no regulatory body stopping/punishing that.
c) Last time I checked, the ISS didn't have a diesel generator standing out back, so it will run on solar power only (which is of course offset by burning rocket fuel to get there in the first place, and probably by burning itself up when eventually returning home)
Why the ISS -> probably because it has a well-understood power, data & thermal framework that the company now doesn't have to build for themselves, nor do they now have to manage the orbit of their node.
Do note that I'm not advocating for ETH-nodes in space, I'm just putting up reasons for sending [stuff] into space. If you had a very lucrative webshop, you could decide to do HA by sending some of your servers to space. It doesn't logistically or practically make any sense, but the reasons for doing so are not wrong per se.