With open style floor-plans you have the look of open doorways but still have the option of privacy when you need it. There are some types of rooms, like a small powder room off of a hallway, where you simply have nowhere to swing a door and a sliding "pocket door" is the only option. The downside of course is that the floor-plan must incorporate space for the pocket doors. A typical bedroom, for example, will generally have the door located close to one corner for maximum wall space efficiency. That means the pocket door will need to slide away from the corner so you'll need to leave a 36" void area to that side of the door. Now, where do you put your light switches? Not a problem that cannot be overcome but one that needs design considerations. My home in Illinois used pocket doors in some areas, (double slide doors into the library and formal dining room), but still used standard doors into the bedrooms.
Have designed and built 3 homes for myself