The Visual Core's main purpose is to bring the HDR + image processing that's emblematic of the Pixel camera — and already enabled in the Pixel 2's main camera app — to any other app that employs the relevant Google APIs. (theverge.com)
The Visual Core does not, as originally indicated, operate in the main camera app, where HDR + is just done within the app and using the main applications processor. (theverge.com)
It's a shame Square Camera's functionality wasn't built into the main camera app, because many people will miss it. (digitaltrends.com)