The first question about wallpaper in a bathroom is not whether the paper is beautiful or durable. It is whether this room dries between uses. If it does, paper can work. If it does not — if the room stays damp for hours after a shower, with no air circulation and no heat to drive the moisture out — then paper will not survive, no matter what kind of paper it is.
A bathroom that dries is one where the air moves, the temperature rises after a shower, and the moisture is pulled out through ventilation. A bathroom that stays damp is one where the exhaust fan runs but the house is cold, where humidity stays high for hours, where the walls stay warm and damp and then cool without ever really drying. In that second case, paper will lift at the seams, backing will separate, and mould can grow on the back where paper meets wall.
Assuming the room dries — that is the precondition — the next choice is paper type. Vinyl-faced paper resists water better than traditional paper. It is not waterproof, but it sheds moisture better. The backing can be non-woven, which is stable and resistant to humidity movement, or paper, which can expand and contract with moisture. Non-woven backing is better for a bathroom. Traditional paper without vinyl facing is not water-resistant and is the riskiest choice for any wet zone, though it can work in the upper parts of the room where splash does not reach.
Paper shows the wall underneath more honestly than paint does. A painted wall can hide unevenness; paper does not. Every ripple, every lump, every joint in the substrate shows through as a shadow. This means substrate prep is most of the job. The wall has to be smooth, even, properly sized, and properly primed before paper goes on. A wall that looks fine for paint can look terrible under paper if the prep is not meticulous.
Seams are the points of failure. Internal corners, where two walls meet, are the most common failure point. The seam is under stress from the walls expanding and contracting with humidity. Around penetrations — electrical outlets, light switches — the paper is cut and seamed, and that seam is a weak point. At the boundary with tile, where wet zone ends and dry wall begins, the paper seam is right where splash rises from below. These are the places where paper lifts first.
Removal later is decided by how it goes on. Paste absorbs into the backing and the wall, and removal can require soaking and scraping. Adhesive that is meant to be removable — often a pre-pasted product or a special adhesive — comes off more cleanly later. If the owner thinks there is any chance the paper will come off in five or ten years, the removable adhesive choice saves months of work later.