1. There is no doubt that breath meditation can calm the mind. What it does is to keep the mind focused on a neutral object: in this case the breath, but in kasina meditations it is the kasina object like a colored disk. Since those thoughts are devoid of greed and hate, if the focus is kept for extended times, the mind does calm down.
This technique had been perfected by ancient yogis and they had achieved even supernormal powers. But the problem is that it does not do anything to get rid of the avijja or ignorance about the true nature of this world or even to get rid of one’s bad gathi (habits and character qualities). Therefore, if a strong sense input comes, old bad gathi will be re-surfaced and that samadhi WILL BE broken. There are many stories about such yogis losing those supernormal powers by the sight of a sensual object.
I know it is hard to discard the ability to be able to get to a calm state of mind with breath mediation. But in the end it is no better than getting “high” with drugs or alcohol. It is a temporary solution to a deeper problem of suffering associated with the rebirth process. That is what Tobias was trying to explain with the statement, “The technique involves no contemplation and comprehension of the Tilakkhana which the Buddha revealed to the world. The question is how one can attain Nibbana without comprehension of the Tilakkhana?”.
Also, see the post: “A Buddhist or a Bhauddhaya?”
2. Another point is that it is good idea to first figure out what is meant by key words like sankhara.
Chigstarrr said: “For example when a gross and unpleasant sensation arises, one has two choices: 1) To react with aversion, which in fact has the effect of intensifying the sensation or 2) To remain equanimous. That is to simply observe the sensation without valuing or devaluing it. This allows the sankaras to rise to the surface and be dissipated.”
Sankhara are thoughts. They come and go. If the thoughts are on the breath, then there is less opportunity for greed or hateful thoughts to arise, and that is what makes the mind to calm down. The statement, “This allows the sankaras to rise to the surface and be dissipated.”, does not make any sense for explaining what happens. That is just a catch phrase.
But bad thoughts (apunnabhisankhara) are really bad vaci sankhara done by one’s conscious thoughts. They are a form of kamma and can bring bad kamma vipaka in the future. So, the permanent solution for the problem involves the mind to get rid of wrong views, habits, and to stay away from immoral deeds (dasa akusala). One aspect of this is discussed in “Correct Meaning of Vacī Sankhāra”
3.The real vipassana is about analyzing why such greedy or hateful thoughts arise, see their bad consequences and to get rid of them. Just by getting the mind off of such thoughts by focusing on breath is not a real solution. If bad consequences of hateful thoughts, for example, sink in the mind, then such thoughts will gradually cease to arise. That is the more permanent solution. This is what is explained in the “Maha Satipatthana Sutta”.
4. So, if one’s goal is to achieve temporary “a peace of mind”, then such meditation retreats will serve that purpose. But if one really needs to understand the key message of the Buddha, one first needs to understand what that is. This is explained in the post: “A Buddhist or a Bhauddhaya?” and in, “Buddha Dhamma – In a Chart” among others.