I hope it's on the way, but I don't think the Pioneer Na is yet a sign of this revolution. This detailed review didn't leave me in a hurry to go get one, anyway:
The idea with really cheap batteries is that they don't need good energy density. You just swap them every so often and put the one you aren't using in the charging rack. You could even carry your own reserve energy with you!
We used to have swappable batteries in virtually all of portable electronics. You could even get them in a rechargeable accumulator format. Virtually all of portable electronics has integrated batteries.
Yeah but AAs suck, and the newer more advanced batteries all have different voltages and require different charge circuitries so it’s hard to create a new standard for them.
It is always the case that custom configurations have advantages over other configurations. But standards give a good trade off between performance vs having a large ecosystem. Integrated batteries just add to the e-waste problem.