Some people are very hesitant about other people going into their house, even if they aren’t strangers.
ETA unless it’s absolutely necessary.
Well, you really can’t hire an electrician to add stuff to the inside of your house without letting them in the house. 
When house hunting we came across a house that must have originally been a very basic cottage style, front door center, back door center, and a concrete exterior stairwell than led down to the basement as well as an interior staircase back to the first floor.
One of the past owners must have wanted an attached garage so they built it on the side where the concrete stairwell was. So I guess if you parked in the garage and were carrying groceries in to stay out of the rain you would haul them down the stairs, through the basement, and back up the stairs to the kitchen.
Just a curious data point: in Central Europe it was quite frequent until about the 1980s to have a separate toilet room and a separate bathroom which were not to be mixed or confused.
Maybe some Europeans can share their experience and let us know if that’s true also for their country.
Too late to edit…
Imagine my slight confusion as a young boy learning English, when English speakers asked for the bathroom when they really needed the toilet room…
;o)
It was at least true for my grandparents’ bathroom/toilet. We all lived in a multi-generational setting in a house that my family had built in 1893, and while my family’s apartment had only been built in the attic in the late 1960s, my grandparents had a single toilet and a separate bathroom. And even that was a relatively new set up (maybe from the late 40s/early 50s), because at the back of the house on the basement floor, there still was a stand-alone toilet you could only reach by crossing a piece of the backyard which had been the only toilet for the whole house (which at some times housed up to 15 people) for the first five or six decades of its existence.