Omally, very correct. All types of assets follow a boom and bust pattern, including things that stick around a long time like real estate and the stock market. I never meant that bitcoin is worthless, just that no one knows the value, so buying it is speculative and risky.
Bitcoin may be around for a long time and become a part of the economy (or it might not for a variety of reasons), but the issue is the price vs. value. There isn't a good way to value bitcoin to know if buying it at $45k per coin is a good price. The price 5 years from now could be much higher, or much lower.
The stock market has ways to evaluate the value to see if it is overheated, like simple P/E ratios or the value of the total market vs. total GDP. You never know where the top is in advance, but you can certainly know that you are buying the S&P 500 today at an elevated price, which will lead to subpar returns in the long run.
But with bitcoin, there is no way to know which part of the cycle you are in. Are you at the bottom, the top, or somewhere in between?
That is what makes it a speculative purchase, rather than an investment. That doesn't mean bitcoin is worthless, it just means that everyone is guessing if the price will go up or down, without any way to analyze or calculate it.
Speculation is ok as long as you understand that it is a risky bet and only put in money that you can afford to lose.