The difference is that players who make the NHL at 18 are almost unilaterally NHL players. There are 31 players who've made the NHL at 18 and played 10 or more games since 95-96 (aka the modern era) - 3 of them (Fata, A. Berg, Fritsche) were not successful NHLers.
Most players who make the NHL at 22 or later are fringe NHLers. There are some that aren't, and certainly there are also late-bloomers who come over from Europe like Damian Brunner, but drafted players who take that long? I don't expect much from them.
This is one of those arguments that doesn't really have any meaning without any context. Sort of like the idea that drafting a defenseman is a more risky proposition than drafting a forward, and thus it should inform your draft strategy. It matters precisely who you are talking about, and not just saying a player got playing time at 18 and will thus have a good career since that's what usually happens, or you ought to be hesitant to draft Adam Larsson over Courturier since the bust potential for a defenseman is greater. Obviously, the vast majority of 18 year old NHLers are top 10 or even top 5 picks in drafts of varying quality. Not to mention the fact that it's the bad teams that are drafting that high in the first place.
Matteau was maybe the only forward that wasn't named Tim Sestito that you could plausibly call up for a significant period of time, especially when you had a shortened season with virtually no training camp which made things a little quirky this year. Under most circumstances and with most teams his arrival time would have been about the same as any bottom first rounder in a so-so draft.
Don't get me wrong, I think he'll be a useful if not good player. It just doesn't have much to do wtih the fact that he got some playing time this past year.
Edited by Daniel, 23 May 2013 - 09:46 AM.