Few DeFi projects still lose money due to security hacks for each example balancer lost 500,000 worth of ETH to a hacker weeks ago, this shows that not all DeFi projects are capable of keep users funds safe, this is not the only problem I'm worried about, scammers have not even start building fake DeFi projects yet, maybe this DeFi story will end up like ICO hype of 2017? What's your thoughts on this?
This is a legitimate concern, DeFi is just a loose group of Ethereum tokens/smart contracts, and it's quite possible that scammers will start making smart-contracts with backdoors or will just pull exit scams. It's also possible that DeFi will make ICO return, with new token scams claiming to be a part of DeFi.
Don't get caught in this DeFi hype, even if it will become more secure, it's still fundamentally flawed - it runs on Ethereum which has growing centralization, a lot of DeFi contracts are very limited in their nature or have some centralization in them.