Since quite some time designers try to bring daylight into the bathrooms. This is definitely a very positive trend. Most of the standard bathrooms are dark and in many cases badly lighted, because they are located at the inside of the building. There are only few examples where the layout of the building and the project budget allow direct windows to the outside.
The layout and size of the bathrooms make it difficult to install a window or openings. To install transparent or milked glass walls at the shower is one way to get around this. The other way is to open the bathroom and to integrate it into the bedroom. Some designs even do not separate the bathroom anymore. Blinds or curtains can be installed to create privacy.
I recently stayed in a hotel where a semi-transparent mirror was installed. The idea is quite good. You have a view from the bathroom to the outside and a mirror from the side of the bedroom.
Glass walls as shown in the picture increase housekeeping efforts for cleaning. Open bathrooms also bring more humidity to the bedroom. This could have an impact on the durability of materials used and the climate in the room, if the ventilation system is not designed accordingly.
Another example provides a separate shower and toilette, but a freestanding vanity in the room, which forms part of the desk.
These solutions may be convenient for the single traveller, but I doubt it for couples. In my opinion the design goes sometimes to far with increased transparency. The privacy of the bathroom is lost. One can have different views on this, however I think even the closest partner deserves privacy in the bathroom.
There is definitely a clientele for these type of designs. But from the point of view of the owners of such properties the question is, if this is a sustainable design or if shorter periods between renovations are required because of a sooner outdated design concept?
The bathroom is beside the bed one of the most important features of a guestroom. It needs all creativity to expand the feel of well designed bedrooms into the bathroom. A decision towards transparency or opening of bathrooms should only be made based on a clear understanding of the focus group of the future guests and their demands.