What you said is right,but consider small income earners, people with very low profits.Saving in home lockers! Very funny, I must say. I hope you do realize that there is absolutely no substitution for saving in a bank.
The best and assured place to save is the bank. The bank are organization that have high security and I can tell you that your money is in safe hands. Even if anything goes wrong, you can be compensated.
Besides there are certain saving in the bank that accumulate interest when left for longer periods of time.
Imagine keep large sum of money in your home lockers? It is dangerous, you can easily spend it and other things might happen.
Some people make a profit of as low as 0.01 dollar a day in my country.
It's not possible for such people to save in the bank.
But with large sums, I wouldn't advise saving it anywhere apart from the bank.