I love the idea especially since we have 2 similar such mods in our house. Both are made of oak, milled and shaped. The one in DSs bathroom has similar hooks to the ones shown for his towels. We have a long- 9 - 10' - hallway coming from the garage that is totally useless space. I asked DH to do a similar set up for us to hang coats, etc during the winter. You have to go half way across the house to find the coat closet otherwise. Securely attached, these are very handy.
I have always used either Command products or good old sticky Velcro to hang pix or other things in both our HTT and TT. The Velcro comes off easily and without damage to the wallcovering. Any remaining residue gets a bit of Goo Gone and perfect! The glitch came when I used the sticky Velcro to attach something very lightweight to an interior door. When I needed to remove it, it also removes the finish. Well, darn! Went to all DHs selections of stain and the doors are not faced with real wood, but a man-made panel, which looks exactly like real wood, except when you try to touch up some stain. Nope, won't accept stain. Went back for the touch up sticks and found that they just left a nasty, waxy mess. Cleaned that off. Since this item is something that's going to hang in that spot forever - AKA as long as we own Rocky - I just got a decorative curtain rod with ring/clips and it looks great. Warning is to check wood surfaces in an inconspicuous spot before attaching. We did manage to mostly conceal the 4 small spots, but I still know they're there. Darn!