In other words, it is a VERY old fashioned battery.
I think it is the ultra-efficient LEDs that make it possible to actually get long lasting light out of it.
A system of “just add salt water” by the user, though, makes it suitable for the Third World, if the anode is supplied with the lantern.
The question then would be price per unit, because you can be sure groups from preppers to Amish would be interested in something that lets you have long lasting light without a fire hazard or the bulk and batteries of solar systems.