At times, I puzzle about R”chaim’s piskei halocho.
They are not “his”. Rav Chaim (I believe) doesn’t “Pasken”, but rather quotes the P’sak of others.
In this case, in Beni Brak it may very well be Assur to wear a watch, as only women wore them. This would be similar to any culture in which certain items are worn specifically by one gender (such as skirts in the US (vs. Scotland), or moss on a troll).