Deflationary Spiral
Some people worry about Bitcoin being “deflationary”, that it appreciates over time. They think it would make people save more and spend less, thus reducing velocity of money and economic output. That economy would come to a halt if no one spends expecting future gains.
There is a simple thought experiment for anyone thinking this way. Imagine you find yourself in an economy where more and more people do not spend their precious coins and expect the price to grow. Everyone would give anything for a coin, but never give a coin for anything.
You, as an owner of some coins, will find yourself in a pretty curious situation. Since everyone values money so much, you can command enormous economic power. When people hear you can give them a little bit of money, they will rush to you and do whatever you say. You can build new factories, feed the poor, bring water to Africa and so on. You can change the world for the better, just like you wanted all the time. Deflationary spiral then will not lead to a global starvation and misery, but to a perfect society.
Of course, you may not be alone in this desire. Someone else would try to outbid you when buying goods and services. So you two would have to share enormous economic power. If anyone else wants to reshape the world, they will join you and compete with you. Ultimately, everyone who cares about building things will do so while everyone willing to work for precious coins will happily work and save money. And then, eventually, when their money appreciates enough, they might want to do something with a small portion of it just like you did.