The question is what audience you'll target?
As you'll try to advertise a restaurant, that is bounded to one particular place in the world, so of course, geographical targeting is very important for you.
You haven't mentioned what exactly and where you try to do SEO efforts. But check out
Google My Bussiness (Formely "Goole Places for Business") https://www.google.com/business/
this is how you can get your Restaurant on Google maps (Apple Maps in USA as important well). And it should be no surprise, that for restaurants people do look up on google maps via their phones most of the time... Hope this helps for the start. Good luck.;)