One can opt to save the keys on a personal computer wallet. The keys will be retrieved only by using a password.
Second, one can also prefer to print the keys on paper and keeping them in a bank locker.
you are right, but the matter is the place that can be okay. And depending how scure is your computer, if is computer everyone touches is not good to store or save your private keys in your computer. People being recommending saving offline as you said about paper storage of private key, but only disadvantages for paper storage of keys is house burnt, if mistakenly house burn by electrical installation or appliances, your private keys cant be retrieved
As long as you keep it wherever you feel safe and no one can steal it from you, but storing the private key on a computer or phone that is frequently connected to the internet is not recommended. It is very risky that someone borrows your computer or your computer can be attacked by hackers at any time and steal the private key. Store it offline and where you feel safe.