I think apps like this could be interesting. Maybe an angle could be to target people who are generally eating lunch by themselves, and just make it a way to pair them with someone else for one meal. So it's less about "meeting up with someone" and more like "sharing a table with someone", to lower the expectations, pressure etc.

I think apps like meetup, where you are joining a group of people with the same interests, is much better for meeting people than the app described here.