This is not the Tai Chi they teach at your grandmother's senior center on Wednesday mornings.
The main style of Tai Chi taught in the US is the one approved as a form of exercise by the People's Republic of China (PRC). It has had almost all of the self-defense movements reduced or excluded and is purported to be useful for health and fitness, which is why the PRC allowed it. Chen Style is obviously and expressly a fighting style, and as such was almost extinguished during the Cultural Revolution. Practitioners held their exercises in hiding until it was safer to teach more openly.
