Anyone want to fund and help me market the play-doh light?
One little ball of play-doh will power the light.

Video at https://youtu.be/VsTFsf1dhbQ

Just a joule thief circuit that lights a light, it can light many lights actually, but one is shown in the video. Its powered by a small ball of play-doh between a small copper plate and a piece of magnesium, I call these play-doh batteries.

The advantage is always a personal opinion. Could be sold in science kits for DIY projects. Or maybe you just want a battery you can stick on a shelf and 20 years later assemble it and wala you have light. Given these batteries when not assembled never drain or wear out. Maybe some kid just finds making their own battery neat, as I said advantage is always a personal thing. Once the magnesium touches the play doh only then does the ever slow process of erosion happen, which happens in all batteries. Which means you can theoretically make them last as long as you want by simply connecting the magnesium metal to the play-doh and then removing it to stop all chemical activity. Running non stop you may get a few months of constant light. But these kinds of batteries dont last as long as my plain water batteries, as they can supply power non stop for decades. Ive got a few projects running on plain water batteries that have been running non stop over ten years, such as what I call the perpetual pendulum, or the spinning motor, and wall clocks. But those use only plain water with no additives. You can add additives to increase their power output at the expense of the electrode life span. Thats why I like the plain water batteries the most,,they seem to last forever supplying non stop power.  By the way the large water batteries can power lights too, And do it a long time, there just big. The version in the video as seen is small, and can be made even smaller. Anyway just a few suggestions about advantages, because everyone looks at such things differently.