I could buy a bitcoin and hope to sell it later. Or I could buy the S&P 500: a market cap weighted set of pieces of companies that will conduct business and grow by the time I have to sell them, and some will give dividends. Which seems better to you?
Determining that one thing is better than another thing (by however means you determine it, I think both are good for different reasons and have money in each) does not mean the less good thing must therefore be a scam, and definitely not a pyramid scheme, which has a specific definition that bitcoin doesn't fit.
Yes, bitcoin benefits from having more people participating in it, but so does Facebook, so does Twitter, so does Youtube, so does the Internet, so does the US dollar, so does the stock market, etc etc etc. That doesn't make these all pyramid schemes.
Historically speaking, if you bought bitcoin at any point and time and held on to it for 2 years it would outperform an S&P 500 index. We can argue about how long that trend would continue, but those who have chosen to invest at least something in bitcoin have made a good investment so far.
Yes, it is a high risk investment, and yes you could lose 99% of your investment. If you don't have a tolerance for that kind of risk, then bitcoin shouldn't make up much (if any) of your portfolio.
For the next few months you would be better off dividing the assets based on your risk profile. Based on current market trends the s&p may go down in the short term so bitcoin may allow you to spread that risk
Bitcoin changes the world: a permissionless decentralized financial ledger reduces payment friction hence boosts trade, gives access to the unbanked/underbanked, helps people escape inflation, etc.
Investment used to mean putting up capital to create or own something that, with some work, would return a stream of income. Farmland produces food with the work of farming. A factory produces goods with lots of people working. A mine produces iron or copper with lots of machines and effort. With the financialization of the economy, lots of people are increasing their "wealth" by speculation and skimming a percentage on transactions. When people start believing that speculation is the only form of investing, society is in for a hard fall at some point.
In FX trading people are putting up capital to create exchange ratios, which is information. Right now people are putting up capital to determine how much coin issued by a central bank with a "deflationary" bias written in code and run and administered by a collective (i.e., Bitcoin) is worth vis-à-vis USD. Something is most definitely being created.
You just described any investment. FX market, stock market, housing, etc. It doesn't make them "pyramid schemes".