I wouldn't want to backpack with it to be honest. In my car? Sure, why not have a cooler sized battery with some solar panels, perfect solution really.
Also never had trouble flying with batteries. They're always in a ziplock and tossed into a bin, then back into my carryon. You can't check anything with a lithium battery, or, you're not supposed to at least.
Precisely. That means you can "not think about it" 4x as much as without it. One of those with USB-C in and a solar charger has gotten us by off grid for years, as well as perfect for long haul travel. No five minutes replaceable mucking about needed.
It's one thing, not a bag of 10, it packs slim, won't slow you down on an all-day all-night "Midnight Madness" scavenger hunt in NYC, and won't get you pulled out of line at the aeroport.