It's being the intangibility of bitcoin that causes people to think bitcoin is a bubble, that they are thinking it could burst anytime. Unlike fiat money that you can see or hold it with your hands and the fact that it is backed by the government. But as for people who are already in the cryptoverse for the longest time, we all know that crypto has a potential and could substitute fiat in the future.
While all that may be true for you, it's pretty obvious that even on this forum most people are into Bitcoin because they see it as a "get rich quick" solution. That's classic for a bubble.
That doesn't mean there isn't an underlying value, just that at the moment it's swamped by the bubble.