I am an EFR and a Red Cross instructor as well as a former EMT. Therefore I understand where EMT falls in the level of care in the hierarchy of emergency medicine. I think it would be safe to say the typical EFR or scuba instructor would not have a clue about which certification requires more training.
Regardless, I also understand that most EMTs and other First Responders do not receive any diving injury training, and as an EMT that dives you probably hove more knowledge on dive injury treatment than most. So, my plug is for you (and other EMTs/Paramedics) in locations where there is a lot of diving going on need to take the DAN diving first aid and O2 administration for diving injuries courses. You will find out about what you don't know when you do. There are differences in treating DCS as opposed to regular trauma or heart conditions. Check it out.