This was a cute little outing. I like that they managed to actually talk about it afterwards a bit, even if she didn't get to the real heart of why- just saying she wanted to do things more for him was enough.
Also, yeah, just like what was said already: the promise doesn't really matter much anymore. He wants to embrace feelings he has now, not old ones. And now Chitoge knows he feels this way, too.
And then that indirect confession at the end. Maybe that'll stir something in his heart. Even if it's a sharp pain, like when Ruri said it about Kosaki, that's still progress. He'll know what it means, at least, because it's a familiar feeling.