Aaron Marino of alpha m. discusses the functioning button hole. Did you even know it was an option and a specific way of wearing it? The devil is in the details with higher end suits. Lower end suits with have buttons simply sewn on.
With functioning button holes, always undo one, sometimes two, of the button holes. You illustrate you know what you're doing. This is the standard way to wear it.
Another high quality detail is kissing buttons. This is when buttons are touching each other. It takes more time and craftsmanship to sew them on.
Alpha has seen guys with high end suits that don't have functioning button holes. This characteristic illustrates the suit is high quality. If you are trying to up your image and game, this detail is somethign that Alpha looks for when purchasing suits.
Modern Tailor (discount Code alpham10) has custom dress shirts for $19 and you can make your own suits. you can chose the functioning button hole option. You can also get contrasting stitching around the button holes.