As far I know the blockchain system is the most trusted system and bitcoin is totally based on that system so, how could it become a bubble.
I think the only difference is that Bitcoin is virtual and the other is physical. Who knows, gold, diamonds and pearls may only be stones in a parallel universe. So we cannot say that Bitcoin or cryptocurrency has no value at all. It took 9 years for BTC to reach that price.
If you think Bitcoin has no value, then gold, diamonds and pearls should have no value too. This is a human who gives value to assets.