If you owned a national currency, you would have the legal taxing authority and guns behind your papers. If you owned gold, you would have a shiny incorruptible metal in your hand to hand over for industrial if not artistic uses, in a pinch. Heck, even if you owned a potato, you could eat it -- and in dire circumstances that has a huge amount of value and maybe you can convince somebody to trade something else valuable.

If you "own" bitcoins, you have some numbers graffitied over people's hard drives. Yes they can't change it because electricity, and the numbers only get so big, and you have some different numbers that can be turned into the graffitied numbers by one particular algorithm that people like at the moment. Without transactions, these properties are completely arbitrary. I don't see how by themselves they can give anything approaching the necessities for a store of value. The truth is, without competitive transactional uses bitcoin has no fundamental value. Without fundamental value it can't be much of a store of value, since literally anything else without fundamental value can be equally good. You can store something like the goodwill of the network, as now, which isn't nothing, but it can be notoriously fickle.