My view on en-suites come from the cleaning angle.
Our first house was a normal small 3 bed semi when we bought it. We did a large two storey side and rear extention and ended up with a family bathroom for our two children and we had en-suite shower room. I realised within months that I never went into the family bathroom, I only ever visited it to clean it after the kids had been in there and when we knew a visit from family or friends was iminent - it was filthy!
Move on 10 years and we moved to our first self build. The children were then 16 and 18 and I designed the house ( yes, myself without an architect) with four bedrooms, all with en-suites plus a downstairs cloakroom for visitors. My whole reason for making each room en-suite was so that I DIDN'T have to clean up after the kids. Their bathrooms were in their rooms, I just made sure their bedroom doors were kept shut, tightly shut to keep any escaping germs, bugs and other unpleasant items in there rather than in my air. When my son moved out and we were getting ready to sell up, I went into his shower room for the first time in 7 years. It was VILE. It took me a day to clean the smallest shower room in the world, but I had lived happily without worrying about how bad the room was for each of those 7 years. I gave them en-suites to avoid me doing the cleaning.
When I design the next house (just starting thinking about it now) there will be en-suites again in each bedroom and there are only the two of us now.