For starters there is a stud on top and an anti-stud on the bottom. Great planning already as these can be stacked in a variety of ways. The wheels stay within the height of a plate so there is no conflict in stacking them. Since they are plate height of 3.2mm that means the wheels must be bar sized. Indeed this is the case as you can pop it into clips. The coolest thing about the wheels is the spacing. It's just perfect to fit on minifig binoculars.
There is a nice touch of an open space between the front and rear wheels through the skate. This helps visually but also gives a half plate gap that will clip with decent clutch over the lip of a plate or brick. Older brick, not the newer ones with skinnier walls and clutch buttresses.
Due to the geometry of the anti-studs under a 2x plate, the wheels will slip in with a bit of clutch, more depending on exactly where you place them. This can of course be used for stud reversal as another plate will do the same action right on top. Once connected, the plates are exactly 1.5 plates apart. Considering that the stud is what limits the plates, this makes sense. A stud is 4.8 mm which is 1.5x the 3.2mm plate thickness.
Of course my favorite aspect of the skates is the size themselves. I am primarily a micro-builder and have recently discovered the joys of the micropolis standard. These skates represent the perfect size for a set of wheels under a semi-trailer. The wheels end up being about 36" tall at scale. Given that the micropolis standard is fairly loose, all else looks very nice.
What else can you do with these skates?