I think Bitcoin has changed over time and circumstances, so it cannot be limited to a specific unit. Bitcoin is basically a decentralized digital currency. Where an individual enjoys the convenience of transactions without being controlled by any center. But from different people's perspectives, it is different. Some see it only as a digital currency, some see it as an investment asset, some see it as a path to financial freedom, some see it as digital gold, and some see it only as a way to get rich. I think it is wrong to limit Bitcoin to just a currency or an investment asset. Because it is a technological innovation, it is also a symbol of financial freedom and decentralization.
Change is always present, and advances in financial technology never stagnate but rather continually evolve. This is interesting to note because we are certainly not experts, meaning we don't fully understand the exact direction. For example, spot ETFs and the entry of large institutions will create many changes, making it more massive, and creating something capable of providing broader merchant integration and more realistic use cases.
Psychologically, most people still believe that those who currently hold BTC don't intend to spend it, but rather hold it and wait for the price to rise, which automatically shifts it to a store of value. However, I also believe this will succeed; perhaps the timing is unclear, as many remain concerned about the volatility that can occur at any time, which is always the reason people shift from using it for transactions to fiat currencies.