He had left the big house in Portland and was more comfortable and could enjoy life more by living in the Tiny House.
In essence, these people, are humans who have gained enlightenment, they understand that all this time what we have been pursuing in life is acceptable to the functional things / essential and really we need.
Large, luxurious house with all the interesting things and other insignificant things piling up and giving prestige, not function.
Instead of following the trend of luxury living, they chose to live anti-mainstream, live closer to nature, and reduce our dependence on things that are less useful. Just imagine, in such a small house, we must be able to be selective in determining what items we will keep