peel and stick wallpaper can be used multiple times, it only requires you to carefully peel it off the wall. As much as it is used permanently at home, This is also good for temporary projects, maybe a video shoot, photo session, rented apartment, hostels etc.
The size of your space determines what colours to paint it, if you have a small room you have to play safe with certain colours because it can make a small room look even smaller or make the same small room bigger. With wallpapers, a wrong choice for a small room will not only make your space smaller it will make it look clumsy and tasteless.