The glass bathroom is the most A/B tested feature in modern hotel design. It exists for one reason: it converts on Booking.com and Expedia. When the major chains compared listing photos with opaque walls vs glass, the glass version booked at materially higher rates. Three things are happening at once. The room photographs bigger. A 350 sq ft room with a glass wall reads as 450+ in a wide-angle listing shot. Guest satisfaction scores correlate more tightly with perceived room size than actual square footage, and hotels figured this out in the 2010s. The bathtub gets seen. Tubs are used in roughly 5% of hotel stays but they're a top-three driver of "this looks like a luxury room" in the booking funnel. A bathtub hidden behind drywall is invisible in the listing photo. A bathtub behind glass becomes the hero shot. The lifecycle math is brutal in the hotel's favor. Drywall around a wet room fails in 7-10 years from moisture. Glass and tile last 30+. A single mold remediation runs into the tens of thousands per room and pulls inventory offline for weeks. The glass wall pays for itself the first time they don't have to gut a bathroom. You're right that it's terrible for groups. Hotels know. The conversion data beats the complaint data, because most rooms get booked by solo travelers and couples who never read the design as a problem. Families and friend groups are the segment that loses, and we're too small a slice for the math to flip. The semi-frosted glass is the apology. The design team telling you they know.