@kevin That is positive, I can't say why they were popular but I suspect the price of entry was less than committing to the non-disposable kit; one of the many ways poor people end up paying more for practically everything.
I suspect many people don't even think about the batteries, my hope is to simply make people aware of the lithium.
One reason is I talk about specifically Lithium a lot
And I like to approach the same science topic from different angles to try out different metaphors