Would be great for Capture to use the built in macOS colour picker tool as this would allow input of hex colours as well as using the colour picker tool to grab a colour from a logo etc
We will not be going back to the macOS colour picker, there were plenty of reasons for us to make a new one.
However, we could look into hex colour information for RGB colours. Probably not picking colours from a logo though. But if you're on Mac, the ColorSync Utility that comes with macOS lets you do that easily.
If HEX was added that would be great:)