Tai chi (taijiquan) is many things to many people, but at its core it is one thing for everyone: natural and efficient movement that produces beneficial physiological results... simply by adding moderate physical activity daily. Whatever your motivation may be, try it out; tai chi undoubtedly can be useful in several ways once you learn some basic moves and practice them.
A Person Who:
... wants and needs more physical activity.
... wants to improve mental concentration.
... wants to do more than an occasional class.
... enjoys interacting with others in educational setting.
... wants to delve deeper in study of the subject.
... is looking for a practice that complements other life activities.
... is seeking healing from injury—acute and chronic.