PS3 Trophies, a way to rival Achievements or a way to sell DLC?

let's add em to our old DLC which isn't shifting!
Sony are being quite sneaky about their integration of Trophies, their answer to Microsofts Achievements system.  In fact I think they're being really 'Sneaky Petes'.

I mean, is it just me or are trophies more a way to reward the developer rather than provide an interesting game mechanic for the gamer?  The reason I say that is that from our one live example and from the news of future trophies their seems to be this way of thinking that it's alright to retroactively add trophies to old DLC?

Stardust did it and news is that Warhawk will.  Who's willing to bet that Pain does too?

It works though, just how many people will buy 'Eden' just for trophies?  A lot, especially when Sony like to ram the fact it supports trophies down gamers mouths (see their recent official blog article entitled "PixelJunk Eden: Oh Glorious Gardens…and Did We Mention Trophies?"

It should be noted that so far there hasn't been an example of a platinum trophy only being available with DLC (the developer of Warhawk came out saying that would suck) but it's something I fully expected and still do.  Perhaps EA's first trophy-enabled game?

I hate this sort of thing.  I know it's all marketing and we must remember that Sony, Microsoft and Nintendo are in it for money after all, but I wish Sony were a little more subtle when it comes to their stealth tactics.