That is totally up to you. You can run these modules from a wall wart if you like. The beauty about a battery driven device is that installation is so much easi

That is totally up to you. You can run these modules from a wall wart if you like. The beauty about a battery driven device is that installation is so much easier. You configure it, use some magnets to put it on your fridge and it just runs for weeks or months. The module serves a very specific use case: it's like a smart sticky note. Easy to place, easy access to the information.