I agree. I come from a contemplative Christian tradition, and we've adapted Mindfulness to Christocentric meditations. I also practice centering prayer, and this is in the Hesychasm tradition of Christian contemplation.
Hesychasm, and in modern times, Centering Prayer as well, are not without controversy. There are people who accuse us of attempting to "empty the mind" and push out all thought, but my goal is to fill my mind with Christ's abiding presence and peace, shifting focus away from my ego and physical body.
Focusing first on the breath is a fundamental building block of this technique, but it is thoroughly a spiritual technique. To rob this contemplative prayer of its Christocentric nature is to eviscerate all meaning and all purpose from it as well.
Mindfulness is not merely a meditation technique, even when understood by mental health clinicians. It is a state of being in the moment and aware of what we're doing, and why, while we're doing it. Mindfulness is especially helpful to people who tend to dissociate, such as a defense against emotional flashbacks or stressful situations. Contemplative prayer is also a way of life and a state of mind, and likewise helpful for this, but only when it's been practiced on the regular, because under stress, we revert to our basic training and become reactive, so it is necessary to internalize those breathing techniques and exercise control of conscious thought.
Many people, myself included, don't realize that we are in control of our thought processes. It's common to helplessly obsess and ruminate over something good or bad. It's common to expend so much energy on unproductive thinking. But there is a more excellent way. Saint Paul tells us: "the weapons of our battle are not of flesh but are enormously powerful, capable of destroying fortresses. We destroy arguments and every pretension raising itself against the knowledge of God, and take every thought captive in obedience to Christ..." (2 Cor 10:4-5).