Why do Japanese people sleep on tatami mats?

Asked the Japanese, there are at least 3 reasons:

1. First of all, to clarify, tatami mats are empty underneath, not directly on the ground, at least 10cm above the ground.

Japan is surrounded by the sea and has high humidity. Tatami mats are well ventilated and can protect against moisture. Therefore, the Japanese in the past chose this way, and the modern Japanese have not given up this traditional thing.

2. Whether in the past or in the present, when people return home or go to a pub after a stressful day at work, they feel comfortable and relaxed when they sit cross-legged on tatami mats.

3. There is also a theory that Japan is a narrow place and tatami mats force beds to be more space efficient.