I've never actually used my metal card. I show it to people for the effect but I'd rather not create temptation for skimming. Or give the wrong impression in some cases. I've allowed it to be noticed at high end establishments and sometimes gotten better service than I might have otherwise.
I also flash it at hyatt's (and have gotten some nice upgrades.. all of the sudden lol)... I've also been given club access despite being only hyatt plat. The new concierge service though just in my experience. If you manage to get a good one ask for their extension as I did, because a lot of them are dreadful.