Yes.
It is really safe.
You won't easily lose your money.
Yes true but if you put your bitcoin in the wrong place you will easily lose bitcoin.

For example you save bitcoin in online wallet, it is the wrong way because your wallet not entirely safe.

This is true, but it's your responsibility to keep it save. If something happens to your bitcoins and you had it saved on a cold wallet and something happens to it, it will be on you. You can't put the blame on someone else in this case.