I have used scuba for detecting several times. I can tell you it isn't an easy task, but it is adventurous and fun.
I mostly detect "alone" underwater because if a buddy is near there is the interference factor of the detectors. Those that don't know, can you believe it is very noisy underwater? When I dive and detect, there is somebody at least near me. If I were to do this at the beach I don't believe there should be a problem there for me to detect alone.
Should someone dive alone of course the answer is no. Last year one of my dive buddies, who is also my partner is a dive shop that we own and a dive instructor with over 25 years of dive experience, almost didn't make it out alive for breaking that rule. He went down to recover a dive belt that was dropped by another person on another day from a pier. He was there with a few other guys but he was the only one with dive equipment. He went down about 35 feet, placed his arm under a metal structure to retrieve the weight belt, and the structure fell on him. His mask came off and the regulator fell out of his mouth. He reached for the octo, placed it in his mouth, and then had to feel around with his hand until he found his mask (this was in saltwater). It took him another 15 or 20 minutes to get the structure off of him. Nobody could help him because the visibility was bad and they didn't know anything was wrong. The fact is even if they did, how would they have got down to him.
Everybody has to know their limit.
I'm sure there are many out there that would go diving and hunting with you. I know when I mention it to friends when I am back in Florida they all seem to want to go.
So yes, it is fun and recommended.