In addition to always having DAN dive insurance, I take trip insurance for international trips in part because my medical coverage does not include out of country needs - and I don't think yours does either. I get my trip insurance at a different provider tho.
The medical evacuation is an important benefit, but that's not in the insurance package actually. It's a benefit of the DAN membership, and has to be arranged thru DAN's emergency desk.
As for the three levels of DAN dive insurance, that varies from state to state in the US. In ten states including mine, they still have the old $30 plan with few benefits, until they can get changes approved state by state - so I always took the top $75 Preferred plan. For our other forty states and for Ontario as well, they offer the new trio with the Preferred plan still being $75 USD, but now it's the middle plan. This causes some confusion in some discussions when some say to get the middle plan.
I've never been a member of DAN nor have I ever purchased DAN insurance. That being said, I also dive conservative profiles and don't push my dive computer anywhere near the limits of decompression diving. There's nothing deeper than 80' I care to see and since we enjoy UW photography we tend to stay shallower than most on ourt dives where the color hasn't been filtered out. Some won't dive without DAN insurance. I think it all depends on the type of diving you intend to do. You can stay shallow & safe or push it to the max and run yourself to the limit your dive computer "predicts" is still safe. DAN insurance is an individual choice. I am conservative so I don't feel the need to carry it.
You like betting against Murphy's Laws, huh? Accidents are rare but they happen, and being accidents - never are planned. I've seen 6 divers leave in ambulances over the years, 3 in one group trip - and none of those had been below 80 feet. Sorry, your false science fails. I hope you have superior medical insurance plus take trip insurance that includes medical evacuation. I have heard of groups with non-insured members injured, taking up collections to hire an air ambulance. :sad: I've also heard of people who couldn't get the money needed quickly to pay for injuries & evacuations. In time, they started taking donations to get the body back.