"If you have been in Taiji for 5 years and it hasn't changed you, you have wasted your time" -- One of my teachers' teachers

Martial arts, in my perspective are fighting arts. That is their purpose and all results will come from that pursuit.

I like to begin from day one with freestyle push hands. It is the laying of the foundation for future success. The essence of Taiji lies in Tui Shou and serious study provides insight into how we deal with people on all levels. It is purely Yin; submissive. It always yields and never discharges. The goal is to never let the opponent lay his force upon you. Relaxation is crucial and also builds efficient movement. You learn to respond and react by touch.

Martially, you develop the ability to not take a hit, not be set up for a throw, and to restrict the opponents movement. It's very similar in principle to BJJ's rolling in principle, but done standing. You always have control over the opponent. You control the angle, direction, speed, etc. The yielding will eventually lead into the execution of technique. When this is achieved, it is called the "Glorious union of Yin and Yang." Basically the hard (technique training) has merged with the soft (Tui Shou training)

In combat the entire training above appears only for an instant. The fighter bridges in aggresively, reads the opponent at first contact and unbalances him, and delivers his power (technique)

The above integration occurs in free sparring.

Mentally, Tui Shou leads to a relaxed mind. The mind handles stress much better and thinks more clearly. Physically the body is relaxes. This reduces physical stress which may add years onto one's life and has been medically proven to lead to a healthier existence into later years.

As far as health goes, all I can say is that I do have a developed sense of touch, and my wife loves Taoist massage, so Hey

A similar process applies to the rest of the training spectrum, but is geared toward technique, structure, Strength, Internal Development, etc.