On suit jackets, there are often pockets that are sewn shut. It's sometimes called pick stitching. It helps the suit-maker keep everything lined up during construction, and can make the suit's lines look a touch better if left in place. Typically the first owner will take those stitches out to make the pockets functional, however some folks don't know to do this, or don't care to. Look closer, there may be pockets there, just waiting for someone to open them up...
Similar temporary stitching is sometimes in place on new clothes to hold the vents closed, both on suit jackets and skirts.
In my earlier skirt wearing days, pockets were a key consideration, and as most of my skirts were pretty 'tame' --simple denim un-bifurcated jeans, so they came with functional pockets. But I was also drawn to some fabrics, patterns, colors or form that had great appeal, but no pockets. I'd do silly things to compensate: stuff my pen pocket, wear a jacket (needed or not) for the pocket space, ask my wife to carry my billfold or keys in her purse....all because I had more of a problem with the notion of carrying a purse AND wearing a skirt than wearing skirts!