Many will never invest any bitcoin in the projects because they do not want to lose. Bitcoin you want to save for the future, but Fiat is to be used for investments without any problems. It does not involve any risks.
When you Invest by Flat and get scammed you can easily trace their company and arrest them because scamming your money, but Bitcoin doesn't . Because Bitcoin is hard to trace (but it doesn't mean impossible to do) . That's why Bitcoin is a good field for scammer.
because it is decentralized. And the fact that it is not yet moderated by the government so if you lost your coin. It is hard to get it back or even trace the scammer. We do not have that security in bitcoin as in fiat. But, the risk is still in us. If we follow the proper process of sending money to others, we can lessen the risk of loosing it if we make it in public or hire an escrow etc...
It is not particularly different with centralized currencies either
I guess centralized or decentralized nature of a currency doesn't have much to do with that. There were plenty of scamming enterprises long before (actually centuries before) the birth of Bitcoin. If you look through history you will find scams and pyramid schemes dated as back as early 18th century. I refer here to, for example, the history of the
South Sea Company. It seems that you most likely talk about the irreversibility of Bitcoin payments but this is only a minor issue (in respect to frauds and similar scheme). There are quite a few of Ponzi scheme companies
active today which are involved with fiat mostly