Of course not a requirement, and Nintendo is fine without them. But it would open up their ecosystem to a whole different crowd of gamers, which I think could benefit them in the long run.
I didn't include it in the article, but I've always thought Nintendo could do it differently by having some extras (like artwork or the like) be unlocked through achievements, to give them more weight than just being an arbitrary indicator of your skill. Give players real incentive to go for the achievements, and reward them with real bonuses. Hell, give them Club Nintendo coins for getting all of them in one game. That'd keep fans on the big N's devices.
I touched on Nintendo's opposition of the achievement thing in the article, and honestly I respect that view a lot. Maybe the better solution would be to make achievements completely optional to the player. Though you may be right, people still do care A LOT about these things, and it would give them the opportunity to reach that audience, or at least try to.