My guess: some combination of believing it could be a good business while helping restaurants.
Now that you know it works, do you plan on expanding beyond restaurants? Wouldn't you like to send text messages from car dealers, record stores, dry cleaners, grocery stores, clothing stores, taxi and ride share companies, landscapers, HVAC service companies, dog walkers, barbers, book stores, home improvement stores, electronics retailers, and so on? You could have phones buzzing with commercial messages a dozen times a day!