It's not a matter of what you see, but what's possible... I like the straps on the Bespin Luke for instance, and it keeps the holster moving with Luke's thigh as well, when posing him. That's a big plus to me since, when Han's sitting say in your Cantina, the holster "hovers" and the thigh-strap's there disconnected. Kind of goofy looking to me.
The vest... Just personal preference for me. It's doable, so I appreciate when it's done... It's like Bespin Han's coat. It could be molded on, but it looks better when it isn't. It adds depth (if done right) to the sculpt, and it's neat if you want to remove the vest then. Kinda like hats being removable, even if a guy didn't remove it... It's nice to have.