I use a lot of rechargeable NiMH batteries in my underwater camera-flash. Yes, the NiMH batteries are an improvement over the older rechargeable batteries. You might say my camera goes through NiMH batteries like **** through a goose.
My experience with NiMH does not inspire me to switch from alkaline to rechargeable NiMH for my backup lights. When I need a backup light I want it to work. I do NOT have that kind of confidence in rechargeable NiMH batteries.
In fact, I have thrown away all of my NiMH batteries. I switched to rechargeable lithium batteries for my camera and alkaline batteries for my flash.