Yes, a major purpose is probably to sell home-decorating supplies. Along the way, many practical tips are offered. If you don't, you'll damage the wall when you eventually remove the border to repaint or re-paper the room. Some of the home-decorating details are rather sophisticated. For example, in the chapter about crown molding, the beautiful technique of lighted crown molding is shown in several color photos.
Emphasis seems to be on painting techniques.
I've never seen so many paint brush and roller photos. Along the way, painting tips are abundant. This is a great book to survey. Read sections that especially interest you, and then think about them before deciding if they could apply to your house, condo or apartment. For example, I saw some sections, such as faux leather, which looked beautiful but which would be too dark for my home.