Samuel Axon, writing for Ars Technica:
Today, Apple quietly began taking orders for battery-equipped cases for all three 2018 iPhone models—iPhone XS, iPhone XS Max, and iPhone XR. The value proposition and designs are essentially the same as with battery cases made by Apple for prior iPhones.
While the cases are probably made well enough, the 30% price hike is unacceptable. I’m not a person that needs extra battery life often, so buying one at these prices and not being able to use it when I go to a newer iPhone makes no sense whatsoever. On the other hand, a good power bank will keep going for years — my 10K mAh Xiaomi is still fine after being actively used for 5 years, it holds its charge, and it cost me around 20-30 USD. And it can also charge all my other devices.