The bumpiness could make nails the better option, although if it's just rough sandpaper texture maybe test by hanging something more durable and see if it falls off. The sticky part on these works fine on matte paint because it's a flexible surface you push on for a bit during install, but it definitely works better on gloss paint or other uniform surfaces.

I can’t say I’ve tried that either but the only place I’ve seen them fail is new paint. The directions say something like two weeks - sure enough placing them one week after painting did not stay but 3 weeks did