The Brooklyn Savings Bank

This leather embossed bank is marked on the front:
"The Brooklyn Savings Bank Established 1827, Corporation of Clinton and Pierrepont STS.
300 Fulton Street
Brooklyn NY
The back is marked "Systematic Saving Spells Success"
The outside binding is marked " Save and Have Benjamin Franklin VIII"
The bottom metal is engraved : "Bankers Utilities Co San Francisco Patented July 3 1923 Made in U.S.A."
The bank is 4 1/2" long x 3 1/2" wide. It is beautiful and opens with a key. I cannot show the whole thing as only 4 pics can be shown. I have a key that works, but I don't know if this key belongs to it. It is well made with copper, brass, and embossed leather and metal engraving. It belonged to my mother who was born in 1920. It is small, fits nicely in your hand and made to resemble a book. I have never seen one like it in all the years I have looked. Wondering how common they are, who got them from the bank-employees or customers etc.
It is heavy and weighs about 12 oz. My guess is that she got it as a child, and that it was given to her parents who banked there. Any other information would be appreciated.