Its quite interesting. I am thinking it is mostly due to the need for stability and then 2% is "hard to notice". It started in New Zealand and spread to other countries. Problem is with definition itself and how it is different for different people - defining it as vector with different baskets by common categories gives better representation, middle class vs billionaires.

Check out bitcoin fundamentals economic masterclass episode for more info: https://m.youtube.com/watch?v=CTA3PKB4PoI