That's a great headline. Unfortunately, the article added almost nothing of technical interest, but corrected it instead. The SALt lamp apparently runs on an expendable anode of unknown composition that pollutes the electrolyte, rather than on the mixing of fresh water with salt. Or maybe the reality is a third option. I'll have to watch for a better report.

Reads like a scam spam from Nigeria! What are the electrodes made of?

The key is the cost of replacing the anode. If it's a relatively cheap metal, like zinc or copper or aluminum, it's a great idea.

LED efficiency helps but something I have been thinking about lately is why do we tend to look to only look to white lighting? In San Jose and San Diego I noticed they use yellowish sodium vapor lighting because they produce less light pollution for nearby observatories but they also provide much warmer lighting that doesn't ruin your night vision.
I replaced my porch lights with 2 watt yellow LED (bug lights) and I wish I would have done it sooner both because it doesn't ruin my night vision and it doesn't draw nearly as many insects as white lighting.
Colors don't render as well as under white lighting because there is only some of the spectrum available to reflect back but it avoids the lighting arms race of having the daylight everything you need to see or serving as a beacon to signal all nearby insects to converge on you. Energy storage is still something that needs to be solved but the amount of light pumped out by many solutions is probably overkill. It probably bothers me more than most people but I find lights that are too bright at night a huge nuisance.

This is obviously old technology, which is proven to work. Presumably one would need several cells to get up sufficient voltage. The question is why doesn't everybody use this?The only cost in the whole thing is some strips of metal for the electrodes. The odd thing about these batteries is they do not need to be charged. I think I will try some experiments myself. Eight hours a day for six months is a phenomenal output.
I can't see the need to spend time with Filipino native tribes, in order to grasp the situation of substituting paraffin lamps with LED lamps. A couple of minutes would be long enough. In fact you don't even need to go to the Philippines.

"the finished product will generate enough power to charge smartphones via the USB port on the side of the device." In other words, about 2.5 watts (5V x 0.5 amp). if that's the total power output, it won't create a lot of light, and presumably it won't create any light when your phone is charging. If it's spare output, great.

Using a steel and an alum can or 2 sets in series will do this too for near free using LED's from cheap flashlights that die. LED's are only $.10 new now.

Similar lamps are available on Amazon. Item GH-LED10WBW.

No, it's not "sustainable" when you make a home brew non-rechargeable battery. And it's not "alternative", because electrochemical cells have been made for ...well, a long time.
Don't they have sun in the Philippines? Charge up some decent batteries with PV cells.