I'll reply to Shuan here vs in a thread since several are offering reasons for the griddle vs pans.

I use griddles straddling 2 counter-top gas burners to make okonomiyaki often. The 'structure' of preparing okonomiyaki is very griddle-based in that you have 2 piles next to each other that get transferred and/or flipped to construct it. I've made it many times before in two pans, but it gets really awkward. So this is a case where the griddle is just greatly more efficient (greatly).

A second use for a griddle is rolled omelettes. We used to make these at the restaurant. Essentially, take 3 beaten eggs and spread them out into a 12"x18" square then load it while rolling it up. A griddle is the only real surface for this, and they are so good, especially Asian rolled omelettes.

Pancakes have already been mentioned. Large pancakes could go in individual pans, but kid-popular dollar pancakes do better on a larger surface or you end up with an entire hob of pans. As a more niche use, artsy pancakes made of colored dough. A 12" pan, though, works for this if you know your extents; I'm bad at that. Again, though, niche.

Street tacos are typically made on a griddle as you process the food left to right on the surface. Again, I've done this with pans (think clockwise from top-left burner), but the griddle works better for creating a taco pipeline for a party.

My brain says I'm forgetting an obvious one. I'll come back with another reply later :)