Lent, has been observed for a very long time by individuals who have made a personal commitment to Jesus Christ and observe Lent as a way of showing that commitment to our savior. When we give up something, it can be difficult at first but most people who do observe lent find that the thing they gave up wasn't really all that important in the first place. Giving up something for lent frees up and lightens part of our spirit so that God will have room to dwell in our hearts.
Sacrificing for Lent can have spiritual benefits, but of course it's only relevant if you want those benefits. If Lent is a chore, or something you do by rote every year, it's worth nothing. However, when used as a way to get closer to God, Lent can be a meaningful tradition.
First off, let me say that I'm an atheist, so obviously I don't give anything up for Lent. But, just as a third party observer, I don't understand it. It seems like something made up by the Catholic church and that wasn't in the Bible, like confession and limbo (also known as baby heaven, where babies go if they died when a baby). So, I just don't see the point. It actually seems like a contest of who can keep their pledge.
I think that if people want to give something up for Lent, that is fine and it should be their decision. For me personally, it would not be worth it. It's not that I wouldn't be able to give something up, but for someone who is not very religious, I don't really see why I would.