The way I understood the problem you would be able to build a computer running Minecraft, and Unseelie would prevent you from using that computer to build an intelligence (as opposed to refusing to build a computer). If Unseelie refused to build potentially turing-complete things, that would drastically reduce what you can make, since you could scavenge bits of metal and eventually build a computer yourself. Heck, you could even make a simulation out of rocks.

But regardless of whether you can build a computer - with a miracle nanofabricator, you can do in the real world what you would do in minecraft! Who needs a computer when you can run around building castles and mountains and cities!