Right now countries typically hold US Dollars, Gold and Oil in reserves. The amount of these reserves is critical for smaller countries. Bitcoin is not on that list...yet.
According to the World Gold Council, the total value of all gold ever mined is about $7.8 trillion. The oil market is worth $1.7 billion/per year. There are also 1.56 Trillion USD in circulation. At the moment, bitcoin is worth around $145.9 billion.
If bitcoin were to become part of the reserve mix for even small countries, its value would skyrocket. I can easily see it having a market cap in the trillions.
This may somehow be the reason why votality is kept as part of the characteristic of bitcoin. I guess this may be a hint but more of a strategy for some. If it is therefore be use as a reserve currency for a specific fiat then it will not be for all. We cannot just make bitcoin something as a rebound for it is something for some of us.