Is coinbase and crypto safe?

Safe in what sense of the word? If you don't take the proper precautions, you can still be identified using crypto, as most coins aren't anonymous by default like Monero is. Coinbase, like 99% of exchanges, is KYC, so you will be identified if you use it without putting your coins through a tumbler or something like that.

Otherwise, you won't lose your coins as long as you write down your wallet's recovery code and store it safely. You won't get arrested as long you don't do illegal things.

A currency based on nothing, backed by no one is always at risk of dropping like a stone. 

sure-up until you Wallet gets emptied by someone else.