For me the benefit of achievements is replay value. Considering many nintendo games have medals, coins, etc the replay value is already there, I don't have a problem with nintendo's strategy.

Achievements for the purpose of flaunting your play time I think is silly.  

Ahp ahp ahp ahp!

I hate false dichotomies. I never claimed that cheevos are a throwaway feature, just that they are not a key component to general sales trends (and you're cripplingly unable to prove otherwise).

Your whole original point is that cheevos are a key feature. They aren't.

Now don't get me wrong, I like them - I'm apparently a lot more serious abotu cheevos in games I like than you are - but they are ont in the neighborhood of "key".

Screw achievements.

You're right I can't really prove they're a key component in sales trends but I do know a few things:

1. If a game is longer than eight hours, people aren't likely to finish.
2. Dangle a carrot and people will follow it
3. Achievements drive peopel to finish games and play the single player component longer.

I actually don't think they're a key feature to sale trends but they are a key feature in 1) getting people to finish games and 2) making people keep playing multiplayer.

You're right I can't really prove they're a key component in sales trends but I do know a few things:

1. If a game is longer than eight hours, people aren't likely to finish.
2. Dangle a carrot and people will follow it
3. Achievements drive peopel to finish games and play the single player component longer.

While the above isn't something that drives sales, it is a key feature to making people experience more of the single player game. 

If they see the achievement for finishing the game or chapter, they might just put in that little bit of extra effort to finish.  If they see there's an achievement for finding collectibles and they have 4/5, they might just start searching nooks and crannies.

I don't believe I ever even hinted at achievements being something that drive sales (or if I did, I in fact did it wrongly), it's a key feature in getting people to play the game and play it more.

Correct me if I'm wrong, but I recall a gamasutra article which featured metrics showing that the number of people completing games has improved little, if at all, compared to the previous generation

I'm not saying people finish more games because of achievements, I'm saying people play longer and differently.

Pretend you're playing some sort of chapter based game and you're in the middle of chapter 6.  On a normal Wii game, you're not getting achievements and for whatever reason you put the game down.  What encourages you to come back?  Enjoyment is a big thing but that's not always enough for people.  If the Wii had given them some sort of over-arching achievement at the end of every chapter they know they're due at the end of chapter 6 even if it isn't the last chapter.  That achievement may just drive the person to play the game that much further.

Now pretend you're playing a game that has 40 collectibles.   One game, lets say a Wii game again, gives you access to an art gallery for getting all 40.  A similar 360 game with 40 collectibles may give you access to an art gallery after you collect all 40 and an achievement when you collect the 40th collectible.  Finally, another similar PS3 title has 40 collectibles and it gives you access to an art gallery once you've collected them all and a trophy every five collectibles.

Now pretend in all those games you're at 24/40 of the collectibles and you're about 2/3 through.  For the Wii game, most people aren't going to care about the art gallery.  For the 360 game, most people are going to give up finding the collectibles because they're surely missed the achievement and don't care about the art gallery.  For the PS3 game, the person knows they're only 1 collectible away from a trophy and they're going to start exploring every corner seeing more of the game.  Furthermore, they've tasted the carrot and they're going to continue to explore the game.  They might not get all 40, they might only get 25 in the end but the achievements still served their purpose.

That little trophy didn't sell anyone on the game at all but it made the person keep playing since they're only one away and it encouraged them to see more of the game that the Wii or 360 person would not have seen.

hmmmm no PS3 or 360 games in your library. 

Don't mistake me; I understand the logic behind the claim.  But I'm fairly confident that the data don't support the claim.  You're offering a hypothetical to support the thesis, and I concede that, in a vacuum, there is a logical connection there.  But to the best of my knowledge, reality contradicts this hypothetical.  Or is there some data that I'm missing?

Hey, I say if the logic makes sense it makes sense.  :-p

Though I would be interested to see your source and when it was written.