Or similar to gold. The use cases for gold are rather limited, especially in light of the market cap. Copper for example, has more use cases.
But you hit upon value: it is what people assign it.
If we, collectively, trust and have confidence in Bitcoin, then it will remain valued, hence the price could keep appreciating over time.
I think it is similar to gold as an investment, but gold actually has a lot of uses. Gold is necessary in electronics, gadgets, vehicles, and space related equipment/machinery. There is also gold's use in jewelry. Compared to bitcoin that literally has nothing else.
Yes it does have some use cases but when it comes to the amount of metals out there, it is minor. Plus, if it is utility that gave gold its market cap, it would collapse.