I think it’s less impressive than you think. Most of the ocean is incredibly deep and the bottom isn’t that interesting. You really need to be (relatively) close-ish to shore and (relatively) shallow to see what most people think of as interesting.
In Florida, where I grew up, the state would sink old barges, tires, cement tubes left over from construction projects, etc. to make artificial reefs. Those were pretty cool because they were near shore and attracted the whole food chain from algae and coral all the way up to sharks and other apex predators. Do that in the middle of the ocean and you just add a new pile of junk that maybe a couple tiny shrimp and sightless fish call home.
In Florida, where I grew up, the state would sink old barges, tires, cement tubes left over from construction projects, etc. to make artificial reefs. Those were pretty cool because they were near shore and attracted the whole food chain from algae and coral all the way up to sharks and other apex predators. Do that in the middle of the ocean and you just add a new pile of junk that maybe a couple tiny shrimp and sightless fish call home.