Like Tiantai, Zen puts emphasis on the mind, but it does not insist that the world is an illusion of our mind.
So both Tiantai and Chan / Zen are more practical and realistic than the ascetic / abstract thinking of traditional Buddhism as originally known in India.
In this way, Tiantai and Zen have developed a particular way of Buddhism that is more in line with ancient Chinese philosophy and Chinese cultural attitudes about human nature.