The Platinum Charge Card give you access to the Plaza lounge in HK and a Priority Pass card which gives access to many other lounges around the world. It's handy, but the big drawback (from my perspective) is that it's for YOU only, so if you travel with a partner then it's useless. Since the only time I use it is when flying cheapo holiday flights with my husband (rather than using a One World or Star Alliance carrier where I have lounge access anyway), it's pretty annoying.
Other benefits of the Charge Card (HONG KONG VERSION) are:
Free ride on the airport express if you spend 6000k on a flight with one of their preferred travel agents, or a free limo if you spend over (I think) 25k;
Free annual worldwide travel insurance (this is the main benefit I get the card for, it's pretty decent insurance);
Various 2 for 1 flight promotions - not worth the paper they are printed on imho, you have to pay "full fare" for the biz class ticket, and usually there are plenty of discount biz class fares available for half the full fare cost anyway!
Various discounts in restaurants etc - but only the expensive restaurants so this is only useful if you eat at fancy places;
Various benefits in hotels - again - very hard to make this benefit work, you usually have to pay some extortionate rate at the hotel when just booking direct with them on the internet is a fraction of the cost!
They also do various other promotions - usually only at the most expensive stores/hotels or restaurants - which annoys me. Just because I have a decent salary and travel alot, does not mean I want to waste my money in designer stores or over-priced restaurants! But if you do, then you can get some nice benefits here.