IMO, & as I am not an international coach, its an uninformed opinion, this is how I see it.
Eddie get players he likes the look of into camp. When he sees them close up in training & in meetings etc, some he likes ,some he doesn't. Some will not get picked again, some may get some game time off the bench, some may get dropped straight into the team. Some may get picked after a period of time working on improving in ways Eddie has asked them to.
Take Marcus Smith as an example. He was brought into camp as an "apprentice" for what ever reason Eddie didnt rate him so he hasnt appeared again. Given his penchant for "solid" 10s who play the percentages you can see why, like Cips, Smith wouldn't be Eddies type of player. I can't imagine either Ford or Farrell scoring that lovely try Smith scored against Wasps last season, can you?
An example of the positive use of apprentice training camp attendance would be Daly. Lancaster had him in camp long before he was ready. He made several bench appearances (memorably as no 8!) before establishing himself as a starter.
I could see Umaga getting international games, as he is much more considered 10 that Smith or Cips. He may well be able to play the way Eddie wants, time will tell.
As for whether is "right" or "wrong", only the coach & the players know that.