History is fun:
"From 1911 to 1966, the United States government operated a savings bank at local post offices. Throughout the early 20th century grassroots agitation to expand the Postal Savings System served as an oppositional political force to the power of bankers."
https://academic.oup.com/jsh/advance-article-abstract/doi/10.1093/jsh/shx036/4110186?redirectedFrom=fulltext