Bitcoins are analogous to gold; both gold and bitcoins are limited in total amount, making them an effective way to store money without paying the "inflation tax". However, there are currently many problems with cryptocurrencies, such as the division into "pure" and "dirty" crypto, and I am not sure that cryptocurrencies are more convenient to use than gold. And this leads to a new question: why the gold is not growing as fast as bitcoins? Maybe buying gold is illegal in the US/Europe?
It is not illegal to buy, sell or own gold in the majority of the countries here in the west, but it can be dangerous depending on the country you live in. Here in my nation and specially in my country, gold is a very big deal, as we are relatively close to mines and mining settlements, so it is not common to see people using gold to buy food, water, paying for services and all kinds of products, that happens in the mining towns, where gold powder has more value in transactions than fiat.
Also, I think you are under-estimating Bitcoin and other cryptocurrencies when comes to fungibility, liquidity and ease of use, not even mentioning Bitcoin can be owned in a discreet manner, without catching the attention of potential thieves.