Bitcoin is an inherently good long term store of value, because it has deterministic and finite inflation schedule, which is also plausibly immutable (contrary to fiat cryptocurrencies, called "cryptos"). On the other hand, fiat currencies are a lousy store of value, because they have non-deterministic, but always positive inflation schedule, i.e. they are guaranteed to lose value in the long term. These are just objective facts about their inherent properties.
In addition, Bitcoin includes cryptographic property protection, making it a better store of value in jurisdictions where local authorities won't provide property protection, or the cost of property protection is high. For example, in many countries, it's illegal to own US dollars. Bitcoin is easier to hide and use discreetly, compared to anything physical.
Volatility is a property of the market, not a property of the asset. All things considered, bitcoin should get less and less volatile when time goes on, assuming that it continues gaining adoption. Which is given, as it doesn't have any competition.