take USDC: you purchase it on CEX or DEX, and transfer to your friend in another country who does not have a US dollar bank account but may have a custodial or non custodial ETH address to receive crypto. they can choose to hold or sell or exchange it for any other asset in the network.

your “investment” in the USD or ETH required for fees is like the fees paid to PayPal or Wise during a transaction. paying these fees doesn’t mean you are now a PayPal investor or have any stake in whether their corporation does well.

if this is all a scam to you then there is not much I can do to change your mind. saying crypto as a whole is a scam is equally as silly as saying the stock market as a whole is a scam. they are both financial instruments at this point with different risks.

edit: the point of my post is to say that you ETH is not about buying the token with expectation that it will go to moon. you can just buy it like you would tokens in an arcade - you use the tokens for fees in transactions in order to accomplish whatever utility the chain provides, maybe with the vast majority of your holdings and interactions in USD pegged assets with no expectation they will moon.