While it's true that Bitcoin's value is largely determined by market sentiment, it's not accurate to say that it can be "whatever you want it to be." Bitcoin has certain properties that make it well-suited for use as a medium of exchange, such as its divisibility and portability, but it also has limitations that make it less suitable as a store of value, such as its volatility and lack of intrinsic value.
Furthermore, the idea that Bitcoin could be considered a piece of popcorn is not accurate, as Bitcoin has certain properties that distinguish it from other things like popcorn. While market sentiment can certainly affect the value of Bitcoin, it's important to recognize that it is a unique asset with its own specific properties and use cases.