How is mindfulness distinguished from other mental health practices?

A few months ago I shared Dan Harris’s definition of mindfulness:

Mindfulness is a skill, generated most commonly through meditation, where you learn to see what’s happening in your head right now, clearly, so that you don’t get yanked around by it.
from episode 52 the 10% Happier Podcast

What distinguishes mindfulness meditation from other meditation practices and from psychotherapy practices? Here are a few questions we can ask to further draw out the distinctions.

On what time scale do the objects of interest for this practice exist? In mindfulness, the goal is always to bring attention closer to the present moment. Rather than dealing with that incident where your coworker said that shitty thing to you, you deal with the present-moment visual and auditory thoughts that are occurring.

What does one do with respect to the objects one deals with in this practice? In mindfulness, the answer is always the same: observe non-judgmentally. Changing external circumstances is off the table. Suppose the object in your awareness is an itch on your nose. The moment you reach up and scratch it, you are no longer doing mindfulness. As long as you’re just observing the experience and trying to allow it to be as full as it wants to be, you’re doing mindfulness.

In doing this practice, are we building up, holding steady, or breaking down objects of awareness? In mindfulness, we’re always breaking down, looking for more atomic parts.