Because it's perhaps the only intersection of: - Large research area - Definitions you can comprehend without a math background - Extremely vague application

Because it's perhaps the only intersection of: - Large research area - Definitions you can comprehend without a math background - Extremely vague applications so that there's no area in which it definitely doesn't apply. I think the hype, which has lasted for a decade now, is a result of there being a lot of smart people in different fields who are interested in math research, but not so interested they're going to catch up to whatever the Langlands program is about.