It's a start but there are others...I don't think all of them will agree 100% with that one. And there are a number of other finishes that they don't seem to carry or have on their list. I don't think I saw Gun Metal there.
Platinum has good wear qualities. It isn't quite as bright as Rhodium but it can be plated thicker because rhodium tends to get brittle when the plating is still very thin. Platinum jewelry is often "flash" plated with a very thin coat of rhodium to make it appear brighter. Same thing is done with white gold. In those cases the rhodium wears off very quickly.
Platinum is easier to work with and can be plated thicker. Rhodium is always applied in a very thin coating because it gets brittle when the coating thickness exceeds about 20 - 30 microns. Rhodium is a little brighter than platinum and is often 'flash' plated on platinum (and white gold) jewelry to make it appear brighter in the store. That plating will wear off very quickly. Rhodium is often used on silver jewelry in a more perminent coat to make it more durable and resistant to corrosion it does not make silver brighter because silver is already brighter than rhodium.
Rhodium is thinner for the reason I gave - the cost would make no difference.