If you’ve used BetterTouchTool long enough you’ve probably realised that BetterTouchTool’s Touch Bar does not work when using Mission Control (Exposé/Spaces, ⌘+tab). This has been noted several times as being a restriction set by Apple that third-party Touch Bar’s will not work.
However, this is not entirely true.
Let me introduce to you Global Gestures.
Global Gestures work even if the Touch Bar is hidden. I use Gestures on my Touch Bar every day, for example: two-finger swipe to change volume and three-finger swipe to change brightness.
If I’m in Mission Control, I am still able to do the above Gestures, even if the Touch Bar is hidden. This proves that “touches” aren’t totally ignored when using Mission Control.
You can change a Gesture to any trigger you wish, including “ESC” (alternatively typing “⎋” by press the actual ESC key)
My proposition: allow us to make some sort of Global Gesture-Trigger-Area feature on the Touch Bar. We could then map out the area for where the ESC sits (ultimately, every Trigger, but let’s keep it simple and talk about the ESC function) and when that area of the Touch Bar is hit, the Trigger — ESC key — is triggered and effectively hides Mission Control.