CFD trading for cryptocurrencies is the profitable type of trading that allows earning money on rising and falling markets. The advantage of this technique is that you dont even need to own the cryptocurrency but predict correctly the price changes of the cryptocurrency. Any kind of trading cant be safe by definition because it is aimed at price speculation and always involves some level of risk.
One of the key concepts you need to know about CFD trading is the leverage that is both benefit and disadvantage at the same time. You can deposit a small percentage, it could be 10% of the trades value but still gain a 100% reward if you predict the price movement correctly. So trading on margin multiple your returns, but if you lose, your losses are magnified as well.
Many CFDs allow you to open contracts on crypto to fiat, but some providers also offer crypto/crypto CFD like for example new platform CEX Broker -
https://cexbro.com/. I think it should be a good broker because I had a great experience with cex, the company that launched it. Anyway, its definitely not a scam.