A lot of phones and laptops can't really run without a battery pack. And you wouldn't want to, because cables are a bit unreliable and you don't want power to blink out, terminate whatever you had running and potentially corrupt a partition just because someone lightly bumped the cable.
But running a permanently connected device with a four-hour battery full of rare materials and wearing that down for no reason is pretty wasteful.
Is anyone making capacitor packs for this purpose? With just enough energy store for five minutes of power and a graceful shutdown?