Biorock Pemuteran is the reason the village is known beyond north Bali. The project uses low-voltage mineral accretion structures to help coral grow, and the result is a shallow reef restoration site that snorkellers can reach from the beach.
It is not wilderness: you are looking at a reef that people are actively rebuilding. That is part of the appeal. Go with a local guide or dive operator so you understand what you are seeing and avoid kicking the coral.