There can be two types: one type is "same fool".  You know perfectly well that the asset is worthless in itself, but you firmly believe that others believe, and will continue to believe, in the SAME value (more or less) than you are going to spend it on.  Gold is of this type.  Famous old paintings are of this type.   It is a "store of value".  This is a belief that can last for a very, very long time.

The other type is "greater fool".  A pyramid game. You know that the asset is worthless, but you expect to be amongst the early birds in a mode phenomenon, where you'll find a greater fool to sell your asset for MUCH MORE than you paid for it.  In order to stimulate this even more, there needs to be a megalomaniac story that it is ACTUALLY a very useful asset of some future important capital with strong fundamentals, but that only visionaries can see it.  Say, the "monetary system of the future".  This kind of stuff always ends in a bang.

Now, go and think: most people buying bitcoin, do they do this because there are obvious fundamentals (which are not a megalomaniac story that won't work if you think about it 5 minutes) ; do you think that most people do it to put their savings safe, without an expectation of a lot of return, just a safety against loss ; or do you think that most people bought it to sell it to much higher bidders ?  What is YOUR motivation ?

Well, then you know in what category we're playing...