My brother lives in the Bahamas because he's been a scuba diver since he was 12 years old.
I buy his big-ticket scuba gear every few years. I asked him about the value of a submarine compass.
He said that they were of great value for open ocean instruction where everything goes gray in the distance.
He said on reefs, you use landmark formations and fin-kicks (100 this way, then 50 left etc) to keep track of stuff
as "shortcuts" get you into grief.
Not me. I worked with scuba and didn't enjoy it. Just work with compressor chainsaws, etc.
I'm very happy with my 6,000 - 8,000' scenery and a good land compass, thanks.