Well, I believe that the true fruits of sitting are not merely tasted by "one pointed sitting", be it on a Mantra, Koan, breathing , the 'Hara', or "keeping the mind focused on the posture". Oh, yes, that will certainly bring about "softening and losing the sense of self", but the result can become a little that "one has to be in the posture (or counting breaths, or reciting the Mantra, etc.), on the Zafu, to 'get there'"....
But the most precious fruits of our Practice are to sit with "what is", life, circumstances "just as they are" which are not apart from us ... and just are us and us them and just are. This aids us in bringing the "lessons" of Zazen off the Zafu into our lives. I find this comes more easily from sitting with "open spacious mind, eyes not closed, fully present with one's surroundings yet focused on everything and nothing-in-particular, dropping the judgments, letting thoughts come and go, finding again and again the quiet space between etc." And as well, that ALSO brings about "softening and losing the sense of self". But by not limiting focus to the posture, it is easier to be "at one" with the whole world and all of flowering life, and to bring it off the Zafu ... which I believe was Dogen's and most other Zen teacher's main point.
That open stillness is our "object of concentration"
Does that make it clear?
If folks are having problems settling down (and need an anchor to hold them down), I encourage them to count or focus on the breath for awhile ... but eventually get back to open, spacious, non-judgmental sitting.
Look, I am just the coach and trainer. Different pitching coaches teach subtly different ways, but its all BASEBALL!