A meal is an event. Eating is the process behind it. Mindless eating, without any awareness of the process itself, turns a meal-event into a belly-aching non-event. A potential of an event, wiped out by mindlessness, is both an existential loss (a loss of an eating moment is a loss of a moment of living) and a loss of meditative opportunity.
Imagine you are in the business of teaching people to meditate, literally. Indeed, imagine yourself as a medieval Zen master charged with managing a Buddhist monastery. Day in, day out you got a bunch of bums banging on your door seeking admission, refuge, protection, i.e. room and board. Unable to read minds and screen out dharma bums from sincerely-motivated seekers, you come up with a brilliant scheme. You decide to turn the dining hall into a meditation hall. You come up with “oryoki” – a highly codified eating protocol that emphasizes a precise order of movements, stopping when you are full, cleaning up for yourself, and liturgical chanting.