How well would it work to walk up to a stranger and ask them to marry you?
You will get rejected 99.9% of the time; however, if you introduce yourself, start a conversation and then ask them for a phone number, it may lead to something more.
Maybe they give you a fake number, perhaps they never answer when you call, or maybe you connect and build a fantastic relationship. See, getting the phone number is a small commitment, and it's easier to say yes to a small commitment and build on that than it is to commit to a marriage proposal from a stranger.
When your marketing strategy is all about creating a direct call to action to visit the restaurant, you are doing the same thing. You need to add a softer sell with a smaller commitment, like getting an email address before asking for a purchase.
Now that you have a direct way of communicating with a potential new guest, you can build trust and commitment through engaging personalized connections.