For whatever reason, many Americans have long tended to associate modernity with the state of California. The appeal of the Golden State translated itself into American culture in a variety of ways, and one of those was architecture. Beginning in the 1920s or so, building designs that evoked southern California themes became popular across the country, especially for businesses that reflected contemporary trends. Movie theaters and motels, for example, often tried to feature a Southwestern "look" ... even in faraway places like Montana.
Here's a great example from Bozeman -- the Siesta Motel, as it looked in a postcard view from the 1940s or so. Back then, the Siesta was at the edge of town, at a major intersection on the main road heading towards Yellowstone Park. Today, of course, the motel is long gone, and its location is near the center of a fast-growing city. There's still a motel at the site, though ... and happily, the current motel is as quirky as the old Siesta was.