After having removed wallpaper a couple of times, I personally would need a lot of convincing to put any up. However, I do really like the look of wallpaper and think it can add a lot of character, if you're willing to take it down when you tire of it.

I would not do paper in a bathroom. Or just about anywhere! Paint is so versatile and you can create so many different textures/designs with it. I'd opt for paint.

i think an oversized paper is great in a powder room. any room with steam tho (including laundry room) it will always be a seam opening up and curling somewhere in the room. if you are vigilant you can paste them back down before something catches on them and tears it a little.

I've seen some nice looking powder rooms on Houzz with wallpaper.