I built my own tiny house, and I can confidently tell you that it is the best investment of my life. The first reason to buy or build a small house is quite obvious, because a small house is much cheaper than a huge mansion, and therefore more affordable. If you are interested here
https://www.boutiquehomeplans.com/the-process, you can calculate the house according to your abilities.
So, when making a choice, think sensibly and soberly to assess your capabilities. In most cases, a mortgage loan is considered the best solution to the lack of money, and the small size of the new house will reduce the loan amount and pay off the bank faster.