This is an interesting question. First, I'd have to say that there isn't much nutritive value to popcorn, especially if it's doused in butter and salt. And corn isn't a staple grain that most people of European decent ever ate until they came to America. As for the digestive tract, whether popcorn is your friend or not is pretty individualized. For people with Diverticulitis it's not a good choice, because the folds or pockets of skin in the colon provide a perfect place for the popcorn (or nuts or seeds) to get easily lodged and cause mild to severe pain.
My dad, like me, has Ulcerative Colitis and is a weekly eater of popcorn without a problem. I, on the other hand can't eat it without GI issues within a few hours.
So, really, it's just how it makes you feel. An apple with peanut butter would be a better choice nutritionally, or even a handful of nuts. But, if your gut can handle it sometimes there's nothing better than a little crunchy, slightly salty popcorn.