alt Hacker NewsThe neat thing about 18650s though is that you can put a battery door on it and make them swappable, if a person used a holder that can accommodate button top protected 18650 cells. The same cells can also be shared by a bunch of good quality flashlights and headlamps. I have several extremely useful headlamps from "sofirn" that take my choice of cell and have a built in USB-C charging port and charge circuitry protected behing a gasket and twist-open ip67 sealed cap. The pouch battery would be better as an integrated all in one product but also makes the thing a bit less modular.
There are advantages in some applications, it’s just not a one size fits all tool. Slim devices aren’t really a good fit for them. They make sense in round devices (like a flashlight) or larger devices where space isn’t as much of a concern.