The bank was built in 1891. The FDIC wasn't around until 1933. The appearance of wealth and institutional stability was a very important marketing tool to late 19th-century bankers wanting patrons to trust them with their money.
The dorm houses kids fresh out of high school who can't / don't want to live off campus. I'd guess the building is attractive enough to most people to avoid negative attention, and -- as the article indicates -- it obviously isn't swaying money away from Dartmouth, so why bother?