The main difference between real banks (NA) and Savings Banks (FSB) like USAA deals with restrictions on lending. There used to be different deposit insurnace funds but they were combined a decade or two ago.
By the way - it appears that USAA does have at least one brick and mortar location with safe deposit boxes by appointment only (but no tellers - do your financial transactions at an ATM there)
10750 McDermott Fwy, San Antonio, TX 78288
Cool. That’d be a long trip to do banking. Lol.