As well I'd like to add the thought that the smart phone could be running all kinds of battery draining things in the background. So actual battery life depends not only mAh but how efficiently the device uses its capacity.

And the camera batteries are replaceable. Quickly. In the field. There are also "battery grips" that have extra battery slots in them and automatically switch between the batteries. The camera never has to sit on a charger, only a spare battery does.

Alternatively: I'd point out that the camera app tends to be a highly battery-draining activity on a phone. Most phone users do not leave the camera app up 24/7.

(And as a digital camera user - at least I can hot swap batteries. I miss my old cell phones that allowed for this.)

Napkin math: 7V/2280mAh = 16Wh or equivalent to 3.7V/4300mAh (USB power banks are always measured and marked in 3.7V and mAh as unit to produce largest comparable numbers)

I've always thought it was odd powerbanks didn't advertise in mWh. That's a bigger number and comparable regardless of voltage.

If you want napkin math then just multiply 2280 by two. It'll be faster and more accurate than converting to watt hours.