I don't think investing in a watchs is a good idea
It is not a bad idea. Watches are also precious and premium, there's a good market on it if you just know which market you're getting in.
after all it is a luxury item and it tends to get cheaper after purchase.
Just like the bags, they are luxury items yet there are plenty of people who wants to have it. You can simply ask yourself despite its expensiveness, there are still people buying it. In one interview about a bag collector, IIRC, she said that bags are also a good investment and that's the same as rolex. These luxury items are not just for show, they have market value.