Marketing hype, mostly.
6.5 Creedmoor won't do anything hunting related that the 7mm-08 doesn't do just a little better. 7mm-08 carries more energy and drops less with hunting ammunition, regardless of yardage. .260 Remington is the equal of 6.5 CM with hunting ammo and at distances less than 400 yards.
With strictly target ammunition, loaded with special target bullets, it is marginally better than the 7mm-08 at distances greater than 800 yards.
If you are looking for light recoil hunting rifles for less than 400 yards, the .257 Roberts and .25-06 both recoil less and kill plenty good.
Marketing Hype? Maybe, but it seems to be working. It hasn't been an overnight success, as the 6.5 Creedmoor was introduced 10 years ago and has only hit it's stride in the past 2 - 3 years. The short magnums were fast sellers when introduced, but today, only the 270 and 300 WSM's are still being chambered and are waaay down on the yearly sales lists.. I was at Simmons Sporting Goods in Bessemer today and the Manager told me that 6.5 Creedmoor rifles were their best selling rifles last year and he expects that to continue this year.
To argue whether the 6.5 CM, 7-08, or 308 is better than the other is just rifle looney talk. High BC match type bullets are also excellent deer killers in any of the guns, which might give a slight edge at distances over 600 yards to the Creed. I've seen a video of a bull elk dropped in it's tracks at over 600 yards with a 6.5 CM shooting 140 Bergers. With the right loads, all will do the job equally well out to 600 yards, which is farther than 99% of the deer killed in Alabama.
Also, a 100 grain Nosler Partition is the cat's meow in the 257 Bob.