While it has lower capacity and is more expensive, the Apple official has a few advantages - it is Lightning so it uses the same charger cable as your iPhone and it can do reverse charging so phone will charge battery if the phone is plugged in. When I’m traveling I just plug in the phone to power and it charges both phone and battery with one cable. It is also integrated into iOS so you can see charge status and control charging from iPhone. Lastly it is smaller than most so it fits easily into a pocket. Basically turns my 13 Pro into a 13 Pro Max in terms of battery life.