The first impression of btc is that you will get screwed by false people that it is a pyramid scheme. The more you study the net, the more you'll fall in love with it. BTC brings that power of freedom and no totalitarian state is going to take that away! That's my thought today about btc.
Bitcoin is indeed a pyramid scheme because its value is based on the investment of the people and the first person who bought and hold will benefits on the purchased of the new investors. Pyramid scheme is not bad since thats how investment work and trading. Those early investors will get profit from new investors as the company or crypto value grow.
Ponzi and Hyip are bad and commonly mistaken as the pyramid scheme. This type of investment just use pyramid scheme but add a catch which user will get passive profit without doing anything.
As I said, I don't see it that way, but it is well known that it is the way you described it, but as I mentioned above, I see bitcoin as a freedom against the state, where the individual does not ask permission from banks or anyone to move their money to whoever wants it and nobody, the interesting thing about bitcoin is that purpose it is a tool to be further explored over time.