Discarded tires quickly become breeding mosquitoes. Under the false guise of helping the marine habitat, tires are often wired together and dumped in the ocean. This method of disposal has several consequences:
Tires release chemicals that are toxic to marine life for a long time until the tires have been completely overgrown with marine organisms.
Organisms that eventually do settle on rubber tires are largely "weedy" organism like stinging hydroids, sponges, and fire coral. Tires never seem to generate a typical coral reef community.
Tires have a large surface area and very little weight so they are easily moved by storm waves, especially in a hurricane zone.
Rubber tire reefs perform so poorly that they often have to be removed at great expense. Broward County in Florida is in the middle of a very costly effort to remove rubber tire artificial reefs that they had misguidedly put down many years ago, with few beneficial results.
On the other hand, rubber tire reefs do provide lots of holes for fishes and can provide a habitat for fish if they are placed in habitat where there is no other shelter for fish to hide (i.e. far from natural coral reefs).
Could a shipwreck become a Biorock reef?
In theory, yes. But because of the large amount of steel, a significantly higher amount of electricity would be needed. A shipwreck powered by mineral accretion would not rust or corrode, making the structure permanent. In addition a much more natural coral reef ecosystem would develop. However, most shipwrecks are so far from shore that very long cables and high power would be needed.