Earlier quoted context omitted.
Yes, but at $19.99 it's pretty expensive. I don't know what the right price point for something like this but, given the fact they are easily lost, definitely HW people on HN, is this impossible at scale?
$5: probably doable. An esp8266 dev board goes for $2 on AliExpress. That leaves $1 for plastics and $2 for a lipo battery.
Was the original/intended purpose to always sell them at cost and make the profits up through increased sales?