We don’t interact with native Apple programming interfaces - we use a cross-platform toolkit for developing the GUI of Ardour. I can find no evidence online that the new touch bar generates anything that would be known to our toolkit (but I also can’t any evidence that it doesn’t just function like an ordinary touchpad).
I don’t know of any Ardour users who have ever tried it. We certainly would have no plans to try to explicitly develop code for the touchbar, though if there were ways to treat it generically (e.g. a second touchpad, perhaps), then possibly some bindings for that would be possible/desirable.