The answer of this question is very simple.

If you're able to trade Bitcoin for anything else of certain value, then the value of Bitcoin is exactly that.

There doesn't need to be intrinsic value in the money itself.

For example, today, the bills in Venezuela are worth less than the material it is printed on. That's a waste of resources.

There's no need to have intrinsic value, money has it's own value depending on many external factors.

Bitcoin is great because it's remarkably cheap to store, operate, use, etc, and it's value is designed to increase over decades.