I don't much care about achievements as rewards, but yes, clearly enough people do care about them that they'd be a good thing to add on a system level.
Where I do find myself using the trophy system is as a historical system. I can scroll through what is effectively my timeline of gaming for the past 12 years, which sometimes reminds me of games that I intended to finish and never got around to, games I had completely forgotten about playing, or games that I had played through and might enjoy re-playing. Every topic about achievements always has a few people pointing out that games can implement their own in-game system, but that function of having a historical timeline is something that can really only be provided at system level, and it's an area where Nintendo's competition have a big head-start.