Didn't read the article in detail, but as someone who is super problematic as far anxiety goes, I can safely say that tai chi practice does help me for the very

Didn't read the article in detail, but as someone who is super problematic as far anxiety goes, I can safely say that tai chi practice does help me for the very reasons you've given : activating parasympathetic system by breathing, active relaxation, connecting mind to body and vice versa, grounding myself (ie connecting my sensations to environment), being in movement (that is, your brain is not thinking about stress alone, but participates in a complete action with your body), etc. (and not the chi/spiritual thing that brings everything together and explains the roots of the stuff but is, often, totally transformed by occidental culture into nonsensical bullshit). But that's my own sample point, just works for me. It's tough to push yourself to practice half an hour a day or so. You have to have the will and when you're tired it's difficult :-/