I thought there had to be variants of the Watch and they were too few. Because watches, unlike MP3 players or PCs, are very expressive pieces of fashion.

People want to distinguish themselves wearing a watch. This is a very new job-to-be-done for a computer company. And I think the reason why Apple enters broadly is, because they understand this.
These three editions and the bunch of straps should be good for a long list of early adopters. But I believe that for something that "personal" you will need far more variety if you want to hold a significant portion of a market like the iPhone or even the Mac does.