Not really exporting energy, the energy isn't being exported to another country. From an energy perspective, they are converting heterogeneous energy sources into homogeneous waste-heat.
I guess not in the traditional sense of the “export” word, but from the foreign trade balance perspective, it’s essentially an export product.
Okay, the bitcoins may be an export product but not the energy. Energy is no more exported here than it would be exported if use with non-metaphorical mining of iron ore. In real world mining you might say energy is converted into a physical comodity, e.g., the ore. In bitcoin, it's converted into a much more abstract financial instrument & transaction verification service.