i dont think you are right, all cryptocurrency are not scam,
yes will all know that some are scam but that dont cartigorised everything as the same they are many legit cryptocurrency that has add value to peoples life, e.g BITCOIN, ETHEREUM, LITECOIN and so many others.
so take your time to learn about cryptocurrency i believe you will understand it better and it will also help you differentiate the scam from the legit once.