A friend recently asked me, is the place where Dre learned kung fu in the movie - The Karate Kid (2010) the Shaolin Temple? No, that is Wudang Mountain actually, a Taoist not a Buddhist temple. In China, Taoism has a much longer history, and many traditional cultures are related to Taoist philosophy. Just like this stone platform carved with dragons and clouds in the movie, what is really placed is an incense burner to worship, not a cobra to practice kung fu.
When we stare at this burner standing in the sky, we can understand the importance of incense and there is an inevitable connection between incense and immortals who live in the heaven. And incense also represents the Taoist priest's desire for immortality.
If we look at the history of human beings, it is not just Taoism, other religions such as Christianity, Islam, Buddhism etc. also use incense to worship the their gods in similar ways. Have you ever wondered why we don't use other objects, but incense to do this?
Of course, each religion has its own philosophy and reasons, let's briefly discuss this issue from the perspective of Traditional Chinese Medicine (TCM) and Taoism here. In order to survive, we need to eat foods every day, like various plants and animals. After these foods enter our body, our digestive system, mainly relying on the spleen and stomach, will convert them into Ying Qi (營氣, or Rong Qi, 榮氣 ). As recorded in Su Wen (素問) of Huangdi Neijing (Esoteric Scripture of the Yellow Emperor, 黃帝內經), Rong Qi is the essence formed from foods, which runs in the five Zang-organs in a peaceful and coordinated way, and spreads out in the six Fu-organs, and then it merges into the meridians to nourish the whole body (榮者，水谷之精氣也，和調於五藏，灑陳於六府，乃能入於脈也). Therefore, daily food provides us with the basic substances and energy to maintain the formation and movement of our organs, muscles, bones, etc. If explained in terms of a Taoist practice, this process can be called as refining Essence into Qi (煉精化氣).
However, as humans, we are not a machine. The biggest difference between human and machine is that we know how to think and we have wisdom. In TCM, This mental part is controlled by Shen (神) or Spirit. For this level, not every daily food can provide this grade of Qi to meet the needs of Shen. Especially in modern society, our food is mostly provided through industrial production which contains very weak Qi, this is why we seem to eat a lot of food but often feel tired all day.
So, what kind of food is the best to nourish Shen? If we consider from grains, vegetables, fruits, meats, herbs, spices etc., we will eventually find, that can provide this kind of high-level Qi are often special herbs or spices which have absorbed the essence of heaven and earth for dozens or even hundreds of years, such as century-old ginseng, lingzhi (reishi), agarwood, sandalwood or some other spices. When we cook and drink these high-grade medicinal herbs, or make these spices into incense to burn, our Shen will be well nourished. Similarly in Taoism, this process can be called as refining Qi into Shen (煉氣化神).
This is why, in ancient myths or some related animations, we can see many stories about incense and immortals. If someone want to summon one immortal, he will burn the corresponding incense. And you can also find that, these immortals never eat our food, their favorite is always the incense.
For thousands of years, those who are willing to be Taoist practitioners, the highest pursuit in life is to obtain eternal life and become immortals. For them, one of the most important steps is to upgrade their Shen through incense, Dan (丹) or other practice methods. Once their Shen is strong enough and reach the highest level, the final step to gain immortality is reached, that is refining Shen back into emptiness (煉神還虛), ultimately achieve the unity of man and nature (天人合一).
For most ordinary people, we don't want to be immortals. Is that incense useful in our daily life too? The answer is beyond question, the traditional incense is an essential food in our life. It can increase our Qi and make our Shen stronger. In this way, we can work and study more efficiently and have greater awareness. In this uncertain world, incense will also bring us more inner peace and happiness, and it's our lifelong companion.