I would think for backlit sub panels, they would need to be hardwired or the batteries would need to be replaced all the time. We ended up putting one of those clear cabinet door bumpers with the adhesive on the light button on each of the sub panels. When it is dark you can just feel the panel and push the button that has the bump. They look like this but much smaller.
I have emailed firefly my information and someone from their accounting department is supposed to be getting back to me.