Bitcoin was built to be a currency. If you want to buy and hold it as an investment, then that's your right - anyone is free to use bitcoin in any way they choose. But if no one in the world ever used it as a currency, then it has no point and no value.
There'll always be people willing to use it as a currency. This is the fact where most of us rely on. We see it as a store of value, but the only value it stores is its future usage as a currency. A similar phenomenon happens with gold. Most of the gold owners, keep it as a store of value asset. A minority uses its useful properties.
All the world's gold is imagined to worth so much, because people know that some will always acknowledge its intrinsic value. That there will always be people who'll use it essentially. And yet,
countries hold most of it without using it essentially.
This is how store of value assets work and I find it completely normal that bitcoin isn't used otherwise. It has the characteristics of the most efficient asset we've ever had.