I continue to find Platinum useful (lots of upgrades and extra perks) and will definitely be keeping the credit card for the $49 cert and 10% rebate. My stays and EQPs usually fall somewhere between Gold and Platinum qualification, but the card keeps that from being an issue.
A couple weeks ago when my 28th 2014 night posted I got an email from IHG offering me a "special opportunity" to re-qualify by staying 3 more nights, which happens to be what I plan to do this month. I wonder what percentage of the non credit card Platinums don't meet the published qualification criteria.