Yes it does help to create boundaries for an area where you meditate. That, for example, is why people go to a Chan hall, because boundaries are already established.
I won’t go into the process of creating the boundaries and purifying a meditation space (anticipating your next follow up question) because it’s too involved. If you have Buddha or Bodhisattva images at home, sitting next to them will suffice.
The Chinese article is inaccurate. If you are afflicted with false thinking (your monkey mind can’t seem to stop), reciting the Great Compassion mantra does not always help. I know because I have tried it more than once.
Your false or scattered thinking results from your conscious mind grasping at internal things or external things. For example, if external sounds (like your neighbor’s television or stereo) annoy you, reciting the Da Bei Zhou (Great Compassion Mantra) is not going to help. In particular, if you are harassed by external ghosts or demons (like those the Chinese article refers to), reciting mantras may provide no relief at all.
You must understand, however, that it’s not because the mantra does not work; it’s because your recitation power is not adequate. For example, a baseball can certainly break window glass, but only when it’s thrown with sufficient force!
In general, when you sit and try to practice Chan, but your mind is spinning: