Based on the description on their site, the controller includes a built-in battery: "8.39 Wh Li-ion battery, 35+ hours of gameplay... "
That was disappointing for me. Specially condidering the Steam Frame's controllers make use of AA batteries: "One replaceable AA battery per controller, 40hr battery life"
AA Batteries might not be as convenient to use, but being able to replace them is a great advantage. All my Xbox360 controllers still work fine, but none of my PS3' Dualshock 3s.
The official docking station could be used to recharge (rechargables) AA batteries so the functionality could remain the same.
Since you're already managing charging things, what prevents you to put your controller to charge when you're done playing?
I don't have to manage charging anything. If I neglect it, and it dies, I just swap charged batteries into it. That's the whole point.
You do are managing your AA batteries: you have a dedicated charger for rechargeable AA batteries, and you put yours to charge when you swap them out. That's just your routine so you just don't consider that it's not bothering.
You could just as well put your controller on it's charging stand/plug it when you're done playing. Or plugging it after your gaming session when it notifies you that it's starting to running low.