Well I'd say it is even deeper hierarchy.
- Having a device's internal battery life long enough to cope for 80% of your typical day so its one device no cables no worries for most days
- For the other 20% of days, having an external battery so you can get through the day without plugging in statically to mains as mains binds you to a spot
- If that time you are bound to mains happens to be for short time (so not overnight) then you want to recharge the devices and the battery you drained fast, so then its a high wattage output PSU, like a Powerport2/4/5.
In this manner then you are mobile, untethered and when you do tether you can make use of short times.
What I do is I act defensively proactive, if I'm not moving, I'm sat down, if I'm near mains I'll plug in begin recharging, so to maintain maximum freedom of unknown next hours. If not near mains then I'll connect battery.
The worst situation is moving with a chain of device with battery, can end badly with cable pulling hard and bending something.