Tatami rooms for sleeping that could be repurposed during the day for something else. They would probably inhabit the room night and day, using it for sleeping and working in. The advantage being that the simple futon would be put away to create the space needed for whatever.
Standing ashigaru armies were only a thing really towards the end of the Sengoku period but a lot of the more temporary yamashiro that would've been garrisoned in times of war would have had perminant barracks/store rooms with the space being utilised for whatever purse necessary.
cheers
James