Indeed, the square format has been the preference of many photographers, including Ansel Adams. For one you never need to tilt your camera to switch from landscape to portrait. Instead you crop in the darkroom. The 12 shots you can fit on a roll of 120 film can easily be contact printed onto a sheet of 18x24 paper.
While the format is often referred to as 6x6, of course the nominal negative size is in fact
56 by 56 millimeters