The reason for removing it is very simple: it wasn’t accurate.
Quote:
Besides the apps we are working on all the time, there are a lot of things that are happening in the background that users may not be aware of that affects battery life. For instance, when setting up a new Mac, syncing iCloud photo libraries can take quite a bit of time. Add facial recognition to that, and battery life is affected even more. Many times, because it’s happening in the background, users may not be aware of what’s draining their battery.
But real time test results show a lot people ARE only getting 3 - 6 hours on light browsing.
There are threads on Apple's site and on Reddit where people have posted how long the battery lasted.