Watt hours has many advantages.
(1) If you know your average mWh per puff, you can estimate how many puffs you'll get on a battery.
(2) You can estimate charging time. USB is 5V, so a laptop port is always 2.5W, DNA's 1A charger is nominally 5W, and a 2A charger is nominally 10W. 10W charger? 10Wh battery, an hour. In reality it takes longer (efficiencies, cable losses, Constant Voltage portion of the charge, etc.) but a good estimate. If the chargers were quoted in Watts (many on Amazon are), there you go.
(3) You can estimate the "C" charge rate. On a 10Wh battery, 5W is 0.5C. (Nominal. At low battery, it's a higher amount of C.) If there are three batteries in parallel, each receives one third of the current. If there are three battery cells in series, the total voltage is three times as high, so after step-up, a third of the current to each again. This works in both arrangements.
(4) You vape at 40W? 10Wh is (10Wh)/(40W)=0.25 hours continuous.
and on and on. Everything is cleaner and easier in Wh.
Inertia is the only reason to stick with mAh. If the battery packs start to be quoted in Wh, then no conversions will be needed any more.
Also, Darkly spectr: Wh is used. My laptop battery is rated 74 Wh. So, it's a good brick to recharge about seven times?
