Very powerful but takes much practice

How so? Compared to the mindfulness focus-on-breath that we hear about?

There's two aspects to meditation: focus and insight. Focusing the attention on one specific thing, whether a statue, flame, the breath, a mantra, increases the ability to direct focus. When focus is reasonably steady and one relaxes into just being a bit, then the insights about how what we think of our unitary self is a composite set of conditions and how composite sets of conditions constantly change, and so on, start to affect our understanding of our body/mind and life and all that. This practice sound like a focus based practice, which are useful and give rise to all sorts of enjoyable mental states (and can indeed be very instrumentally useful for managing anxiety or increasing performance or that sort of thing), but not really the same as loosening attachment to the ups and downs of each moment.