I had a plug that went with rechargeable batteries or something, and it was great for a while, but then the connector failed and if I moved at all the gameboy would turn off. very frustrating.
So instead you like going on a mission, getting distracted and killing a bunch of people/ghouls/irradiated creatures and managing inventory ( I do too).
I just decided I was going to play moonlighter last night as an easy pickup game. I checked the inventory once and remembered I would have to sort and store stuff and immediately turned it off.