Kiosks require brick and motar overhead issues and consumer awareness, marketing costs and efforts.
Free standing units teathered to end seats in random rows in high traffic terminals offer the instant gratification factor, and with card swipe, an ongoing revenues stream opportunity...but it would require an outlay of capital initially and ongoing maintainance, which is not a big deal.
Certainly worth a trial to gauge the market acceptance, don't you think? It's not like they are too busy right now...lol.