Meaningless?
Absolutely.
However, that doesn't stop me from seeking them simply for the sake of seeking them. I don't go out of my way to ruin a game simply by going for Impossible Achievement A or Obscenely Long, Drawn Out Achievement B, but gaining those points for completing certain tasks has a certain pull to it.
It's the rare game that makes me seek every achievement. Only one so far was Oblivion, largely because they were all associated with exactly what I wanted to do with the game, which was see all it had to offer quest-wise. So those were money in the bank, as those simply happened as a consequence of pursuing that goal.
Fallout 3 is the only other one that has had that draw with me, and I only have one left there. Silver Tongued Devil. Which is turning out to be worth pursuing, because I had no idea how many rad, random, unique, and downright hilarious dialog trees I had overlooked in my umpteen-million playthroughs of that game.
Mostly other than that, if I get one randomly through playing, neat, otherwise, I don't actively seek them.