In terms of being your own bank. It is not sufficient that you just have your own private keys stored somewhere on the internet. In cryptocurrency, there are also problems occurring similar to banks where people can have their money stolen. For you to secure your funds, an offline wallet is a must especially if you are to store thousand dollars worth of cryptocurrency. This
article can help you in choosing which hardware wallet suits you and we'll help you up to set up your own bank.
He never said anything about private keys, all he was saying is that we cannot trust any of the banks anymore. I guess the guy is experience in terms of financial stuffs, I bet he won't get scammed easily as he was being cautious from the first place with the monopolizing people.
Any way for the cause of Bitcoin I am also accepting payments of thru Bitcoin, I am running a printing shop, even though small it can barely manage to continue. Sometimes people wonder what is the QR code outside and just tell them straight about it, if they are interested then I give them more basic knowledge.