Brass is becoming less of an issue with all the new manufacturers turning out 6mm and some 22 CM brass. You can always form from 22-250 brass too.

The Creedmoor could be loaded down to 22-250 levels or slightly less and then would most likely have a longer barrel life than the 22-250 due to pressure and case geometry. Both good and unless cheaper factory loads are a consideration the CM may be more versatile especially if twisted for the heavier bullets.

If used for varmint shooting it would be best to have two or three rifles to rotate and keep the barrel cooler. I would pair the CM with a 223 and use the CM for longer shots only as much as possible. A fast twist 223 & CM would be a good combination.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli