I've also done many healing modalities, including somatic experiencing.
From my perspective, we have taken "Buddhism" and "meditation" and we have done what us Westerners almost always do: we boil it down into "stuff that does stuff" and "everything else".
We are so intensely and impatiently interested in "doing stuff".
So, we have taken a tradition/religion that has existed for thousands of years, includes many practices and parts, and we have pulled out the part that "does stuff", and we call that mindfulness.
But, if you really look at the tradition itself, particularly in non-Zen forms of Buddhism, what you often see is what are called "preliminary practices". Used to, if the Westerner goes east in search of meditation instruction, he or she has to get special permission to skip the preliminary practices.
And what our preliminary practices? In the West we call that therapy.
So, this really important thing, that one must do therapy and what they would call in the East "purification" before one is ready to start meditating has been tossed aside because it doesn't yield immediate results like a few days of mindfulness.
In addition, the traditions are almost totally unaware of our understanding of trauma and the best they can do is use the language of "demons".
So, I'm aware of "mindful-based stress reduction", but I'm not intimately familiar with it. It doesn't make sense to me why someone would use mindfulness to reduce stress or in place of a therapeutic or trauma modality.
I mean, sometimes it is way more comfortable to not be aware of things than to be aware of things. And, in my experience, becoming aware of oneself is just a bunch of not fun realizations, including realizations like "I'm a people pleaser" or "I always sabotage relationships in a similar way".
These realizations are not fun because just seeing the truth or the pattern doesn't change it, so you sit and watch yourself doing the same shit over and over and not quite having the power to change it... That requires much deeper meditation and awareness.
At any point in this process, one can become too aware and too burdened with one's issues, and that can result in all kinds of stuff including breakdown and psychosis.
At the end of the day, meditation and mindfulness and all the rest is basically just the matrix movie... Don't take the red pill unless you really want the red pill because sleepwalking through life unaware of one's issues and happily eating the steak that isn't there is sometimes more pleasant.
Meditation is for those who want the truth, regardless of whether it feels good or not. For everyone else, there's therapy.