Look.
Imagine an otherwise empty room with a table and a few chairs. A couple people come in with some money in their pockets and cards. They play a few round of a card game, some lose, some win. When they leave, the room as it was before so it is crystal clear the sum of their money couldn't change. Some won, some lost but overall the change is zero. This still doesn't change if, for convenience, during the game, they use plastic chips to count wins and losses and at the end they exchange it for money.
But if someone takes a small cut every time the plastic chips move then that person is guaranteed to win and everyone else together is guaranteed to lose. Now, a game where, without knowing anything about the game you can tell ahead of the time which group wins and which one loses is not a game, it's a scam.
Indeed, one of the best moves for players is not to play the game but to sell their chips -- and praise the game to increase the chance of a greater fool buying in. Those will sit on a greater loss than you did which might not materialize yet but it's certainly in the system.
So, any crypto"currency" with transaction fees is a scam. Those who collect transaction fees are guaranteed to win and the rest are guaranteed to lose.
And no, stocks aren't like this because they produce dividend. And no, gold is not like this either because there are uses of gold which transform your gold into higher value products than raw gold (integrated circuits, jewelry) which sell for real money. Neither can happen with crypto"currencies", there the only interfacing with real money is exchange.
Is it often used for scam? Yes. But so is email.
Just like stocks can fall 99% in a day. It stock s cam? No.
The problem is that users dive into it without understanding the risks. Also, there should be (and will be) more regulations around it.
But it is as far from the scam as it gets.
Correct. Only a few cryptocurrency projects will survive and the several meme cryptocurrencies or non-compliant coins will wither away.
This is why some companies waited for regulatory clarity to enter back into the cryptocurrency markets. This is what the absolutist crypto-skeptics or absolutist crypto-maximalists won't tell you.