Bitcoin has flaws... in your world the price of Bitcoin would keep inflating until only one currency remained (BTC), nobody would spend any money for fear of its value growing the following week! Why buy a car this week if its cheaper next week?
Your argument has flaws as well.
Why buy a computer today when you know that the same computer will be cheaper in a few months?
Why buy a nice camera today when you know that the same camera will be cheaper in a few months?
Why buy a TV today when you know that the same TV will be cheaper in a few months?
Why buy a smartphone today when you know that the same smartphone will be cheaper in a few months?
Especially in electronics, things get cheaper (and better) pretty soon. It doesn't appear to me that people don't buy them because they will be cheaper (and better) tomorrow.