Using a wallpaper primer offers several benefits when hanging wallpaper. Firstly, it helps to create a smooth surface on the wall, making it easier to apply the wallpaper and ensuring a more polished finish. Additionally, a primer can prevent wallpaper paste from soaking into porous surfaces, which can cause the wallpaper to peel or bubble. Furthermore, a wallpaper primer can improve the adhesion of the wallpaper to the wall, reducing the risk of the wallpaper lifting or curling over time.