Bingo. 18650 is the best, most robust and energy dense form factor right now. Probably for the next while too. It's a primary form factor in the majority of EVs and in some cases you can sub in 123 cells in a pinch. Something like 3x better ED per weight compare to NiMH. Disposable is convenient but heavy and so dang wasteful.I used to think this way. But when your out in the bush/backcountry, your not likely to find someone selling batteries. 18650 or similar cells have a ridiculously high power density, and they can be charged from a vehicle, portable power pack, etc. Or just bring a spare pair.
My 25$ amazon headlamp with 18650s lasts well over 20 hours on high power. I expect to get a few hundred charge cycles minimum from the cells. If I drop it in a lake, it gets stolen, or stepped on, no big loss.