To me what you suggest sounds somewhat conflicting. If bitcoin might be a good store of value in the future, it might be a good investment today. Which means good store of value, but a big dose of risk.
I guess other way to say what you are trying to say would be: "Bitcoin is a very bad store of value for those with a low risk-preference."
"store of value" has a standard usage in this area, and you aren't using that definition.
To be a good store of value means that you have predictable recovery, which is the opposite of what you are say. BTC may or may not be a good (high risk) investment at the moment, but it isn't a good store of value.
I guess other way to say what you are trying to say would be: "Bitcoin is a very bad store of value for those with a low risk-preference."