Well, to be fully in that "space" of Witness is in fact Enlightenment and that is a lofty height very, very few attain (in one lifetime?). Still, it's a worthy path to walk whether one attains it or not. Better Karmic load for the next incarnation.

Here's one practice I find even better than informal mindfulness practice during the day. It's the Karma Yoga practice of Work as Witness. What one does every time one remembers is to "realize" one is not the doer but the Witness. Mind-body is cooking, driving, showering, walking the dog, thinking, typing, etc... and I am just the Witness of the work.