Inside 400 yards there's no significant advantage of the 6.5 Creed over the .308 for most applications/shooters-especially if you don't handload.
Much more ammo selection in .308, over a wider price range.
I realize the 6.5 Creed gets a lot of press- and no doubt its a great round for a lot of reasons- but at closer ranges like this, there's little significant variation in drop and drift between it and numerous other chamberings.

If you intend to go to 600 and further, different ballgame. But again, keep in mind your ammo costs. The .308 is a capable, affordable round which allows those that shoot factory ammo to send a lot more lead downrange for their buck- and that's critical for developing the skills needed to shoo at longer ranges.