Growing corals can be big business, the cool looking ones can be highly valued for people’s fish tanks and harvesting is very sustainable if done correctly. If ocean acidification accelerates though it won’t matter, most corals are very sensitive to ph and water temperature. If the water gets too acidic or too hot most will die out and in general low ph significantly reduces growth.
Sending electrical current through growth frames can cause them to grow/regenerate even in very harsh conditions, though I don't know the exact extent of wishful thinking behind biorock building. To my knowledge, the more pressing problem behind coral's sensitivity to external conditions is algae bleaching, which impacts everything from sand production for nearby coasts, to biodiversity and biomatter production in the area.
Sounds like you are referring to this article. Which btw was a fascinating read http://www.globalcoral.org/_oldgcra/reef_restoration_using_seawater.htm