There are many factors that make bitcoin have value, as you mentioned, the greater the demand and less the supply of bitcoin, the greater its value. The value of bitcoin is represented in its scarcity, as there is a limited amount of bitcoin supply, and more than that will not be available in the future. Also, the trust factor plays an important role among investors in increasing the value of cryptocurrencies in general and Bitcoin in particular. Also, the benefit of using Bitcoin and its centralized characteristics and its most secure and common network is what make it have a high value among most other currencies, In addition to the adoption of Bitcoin by major companies and institutions as a method of payment, which increases its daily use cases and leads to an increase in its value.