THIS JUST IN – AS HEARED DIRECTLY FROM RAV CHAIM KANIEVSKY HIMSELF:
The reason that the Chazon Ish held that a wristwatch is considered “begged isha” is not just because women wear or wore wristwatches, but because the ORIGIN of wearing a wristwatch was begun as an ORNAMENT FOR WOMEN.
Thus the Chazon Ish held that something which began as something exclusively for women’s adornment does not become muttar when men also begin wearing it. [Thus the difference between wristwatches and shoes, hats, etc.]
Pocket watches are clearly permitted even by this shita.