From what I have seen the resale market for these bracelets exists but is fairly flooded with inventory, so the likelihood of being able to resell easily is pretty low anyways. So why not customize and have something unique to you! I probably wouldn’t bother just having it customized to look like an existing Cartier piece though, if I’m doing something custom I want it to be really unique to me. I love the idea of “Cartier x me”! If I’m customizing something like that I won’t be planning to ever resell it, and there wouldn’t be any need for Cartier to touch it as the customization jeweller can care for it.