On this video from you tube the guy made a code with ChatGPT.
My question is how is this safe, is that a scam, and should that be used ?
Thx in advance and best regards. 
Whatever videos we see on Youtube or any tutorial are not made for production level code. This applies on any kind of code, web2 or web3.
Especially this video about creating smart contracts with an AI model, is definitely not safe. ChatGPT has not yet attained the level of producing secure code.
But we can surely use it to create boilerplates OR template codes.
I wouldn't trust AI code if you are not a developer. It can be usefull for simple and repetetive tasks so that you don't need to write the same code over and over again, well there are other solutions for that but AI is one. But it perform very bad at custom code and likes to introduce logic errors. Either learn programming or hire a professional. If you are in need of a smart contract or want to build a whole project then you can contact me on telegram: @solidityX