Interesting question - what does a 22 creedmoor offer over a 243?
Not much, but then there is no shortage of overlap in today's ballistic field. I like the case design of the creedmoor and think it is a good design.
If manufacturers ever get serious about pushing a 22-250 w a factory fast twist barrel, and start loading 22-250 with long bullets, there may not be as much experimentation on the fast 22 side of things.
And i guess it depends on what you want to do with it. I ran JP Rifles Blue Steel Ranch for over three years, and got to see a lot of different calibers come through there. The 22 Creed worked well at distance, but then so did their Valkyries, but that's another thread. As the gentleman noted above, it also works well in the hunting side but it is not exactly fur friendly lol.
I guess that's why there are multiple 6.5s, 6MMs, and 22's. We all seem to be looking for that extra " felt recoil, barrel life, terminal performance, case life, what ever"
The 22 Creed also works well out of several ARs I've seen or shot.