My sister once gave me a Think Geek gift certificate[1]. I decided to buy a pair of these for myself and mah hunnybear.

My pair of chopsticks upon some rests I folded. Notice the tips’ worn finish from use.
At the time I got them because sushi is Mah Hunnybear’s and my favourite eat-out option. I figured if nothing else we can look cool and save a few bamboo stalks over our lifetime, but I didn’t fathom their true value. I still don’t, but I am wiser about their advantages now than I was then.
RATE-LIMITING
You know how this works: open a bag of chips. Eat one chip. Eat another. Hey, two chips at once! Ooh, munch on a fistful at a time! It’s easy to go from enjoying the taste of your snack to mowing your way through imperial gutloads of it, hardly even noticing it as you chow down.
Make the most of your snack. Enjoy every bite. Eating it with chopsticks will maximize the snackiness and minimize the gluttony. Even a consummate chopsticker won’t chow down nearly as fast as a monster mitt-mouther. All the better if the snack motivates you to improve your chopstick skills.
CLEAN FINGERS
Speaking of a bag of chips… ever go to play poker and halfway through the bowl of communal chips (the crispy crunchy ones, not the clay ones) you find the deck is more greasy and yet more sticky than before? Ew! Enough to gross you out but not enough to see through your opponents’ cards.
On the other hand (heh) if you eat your snacks with chopsticks you needn’t worry about griming up your cards with grease.
BETTER HYGIENE
Ideally, everybody snacking from the chip bowl will wash their hands, only touch the chips they actually take, use one hand for grabbing from the bowl and the other for stuffing into mouth, etc. Sadly, these ideals are rarely met. Instead, a group of unwashed hands are simultaneously groping cards, grabbing chips, stuffing maws and licking fingers. Ew!
A perfectly polite chopsticker might reverse their sticks, using one end to grab from the bowl and the other to drop into mouth. Even the rude boors are better off, though, as chopsticks have much less surface area to cross-contaminate than fingers, and they don’t touch as much non-food stuff as fingers do.
Nowadays I find myself using chopsticks more and more often. While I have yet to use them on a bag of popcorn at a movie, I generally do for eating a bowl of popcorn at home as I read — keeps the pages clean. So far my greatest food challenge is actually Chinese food. Chicken-fried rice is not sticky and it’s hard to get decent sized scoops of it onto these chopsticks. (I suspect the secret lies in (a) using broad-tipped chopsticks or (b) using a bowl and shoveling)
[1] She knows me well and often presents me with ThinkGeek birthday presents.