Bitcoin is a group of technologies, the one that creates Bitcoin's "value" is a digital implementation of scarcity. Usually digital things are easy to copy infinitely, so Bitcoin's implementation of scarcity is one of its core innovations. Scarce things inherently have value in society, beyond the material themselves, because we primarily make transactions (trade) using scarce things. In other words, scarce things are useful simply by being scarce. So if you take there's value in something being purely digital, and decentralized, then Bitcoin has value through its implementation of scarcity.