"An economic bubble or asset bubble (sometimes also referred to as a speculative bubble, a market bubble, a price bubble, a financial bubble, a speculative mania, or a balloon) is trade in an asset at a price or price range that strongly exceeds the asset's intrinsic value."
Seems like a reasonable description of bitcoin to me
I have yet to see a well thought out, rational, specific description of the intrinsic value of bitcoin. If it is the case that people think it will either be zero or a trillion market cap, that suggests to me that people aren't thinking seriously about the real world end game for bitcoin and thus that there's is no solid bounding of the potential intrinsic value
Bubbles are formed by people who think they are being rational, but in fact are not. One sign that you aren't being rational is when you don't think critically, quantitiavely, specifically and probabalistically about possible future states