There are two ways to see the question:
- Does bitcoin match the literal definition of pyramid scheme?
- Is bitcoin a bad investment, bubble or otherwise scammy business?
In the meaning 1 the question is off topic as non factual, nor we can safely assume our interpretation of intent is correct, in the meaning 2 the question is opinion based.
Is the question representing the claim fairly that btc is literally a pyramid scheme? Because I think all it was meant is "it's a big bubble" and we are not really addressing the point as it was meant, so we're just adding noise to the internet.
In other words. I dispute the notability of the literal interpretation.
In either case, 1 or 2, the question needs work so I closed it.