Well, that’s true, but you went to the other extreme of the spectrum: Piaget’s specialty are ultra thin watches, I don’t think it’s a much better example.

Mechanical watches under 7mm are already considered thin; more usually they are 9-11mm. Quartz are easily thinner.

I think smartwatches currently around look thicker because of case and lugs design. For example, the Sea-Dweller is 18mm, but the side of the case is not flat all the way like the 360, the case back is actually inset, so it’s less noticeable.