The pictures made it look expensive. And the OP mentioned the coolant being expensive. Numbers would be more persuasive though. In any case, the heat is still expensive to make, and long-term, competitive mining operations will have to make good use of the heat they produce. Versatility will be a strong advantage here, and scaling up would appear to diminish from this.
They look expensive, but remember this is mostly passive. All we have here is helfty shelving, aquariums full of expensive coolant [which isnt consumed], piping and then a few high flow heat exchangers [read NOT AC - so only power costs of fluid flow]. You couldn't design this to be comparatively cheaper if you tried,