I have the 15" MacBook Pro with Touch Bar. While the TouchID works great, I have noticed that it isn't always-on as you know it from smartphones. Whenever my phone's screen is turned off, I can always rest my finger on the finger-print sensor and it will unlock the phone immediately. On my MacBook Pro, I have to wake the screen myself from the touch pad or keyboard and then I am able to use TouchID. I usually lock my computer when I'm away, but don't close the lid. Any help is appreciated!