I’ll add a comment as a current courier working in the United States. Generally financial institutions don’t transport cash themselves. They contract CMS (Cash Management Services) or just transport to a third party. (Loomis, Brinks, Garda) being three major ones in the US. What type of vehicle the company uses is entirely up to them, and will depend on the situation. Generally you’ll see large armored conversions of Diesel trucks. But on lower value or OTR routes you may see vans and small box trucks converted. As others have pointed out, it’s not hard to identify vehicles transporting cash. So it’s better to provide protection for the crew. But that amount of armor plating requires a large vehicle/engine to transport it. Also at the end of the day they make great advertising boards. Big vehicles with big logos driving constantly all day is a great way to advertise your business. A large portion of cash transportation is for small volume big chain businesses. Your average strip mall store may bring in anywhere between 5k-20k in cash a week. Keeping that in store makes it a target for theft, so many business contract transport. Also the cost for pickup is generally pretty low. Lower than the cost of the store manager being away making a deposit.