I don't actually think much of that jewelry is purchased. Most of the time its on loan for those gala events especially the Academy Awards.
That being said any number of types could be into this for various reasons. Fe-doms like ESFJ might want to show off and be the talk of the town. Se-doms might just like to adorn themselves with beautiful things, or use jewelry to make a statement or in symbolic ways like a lot of ESFP rappers do (think Flava Flav). I would think Te/Ti-dominants are probably among the least likely to do something like this.
I wear fake stuff from target so I don't have to worry about losing $X,XXX cash value in jewelry for every day wear. No that's a lie, I barely wear jewelry. I wear the nice simple expensive stuff at gala's. There's not much action there other than, Ha-ha-ha's and how're yous anyway.