The main difference between a normal watch and the smartwatch is that there is physical interaction while using it. we use it as not only just a watch but also as a small smartphone.
After several years of experience of smartwatches, I defined a problem ; whenever I try to check or input something on the watch face, I had to turn a wrist toward my face, which was hard on my elbow joint. D12's watch face leans at an angle of 12 degrees. It is easy on the joint and it helps enhance usability.