I don't think there is anything more valuable for a person than to hear that someone else is thankful for their existence.
Life can be pretty rough at times, feelings of insecurity may fill our hearts more often than not. I would dare say that every human being on this planet has gone through a rough time, full of disappointments, failures, losses and has also believed that life can just be too hard. That no one can 100% understand them.

The problem is that people don't really tend to listen to themselves, a simple "you did good" doesn't have the same impact when someone tells it to oneself. So I don't think there is a more valuable thing someone can hear from another human than a a simple thank you; ''thank you for being born, for being here''.

I think this movie is just about that. The complexity of humans and that no matter how different we may be, there is an internal need of a person listening that someone is there for them, that someone truly cares, that there is a reason that they are here and that they are loved.
Even if they feel helpless, trivial or even if they are fully satisfied with their lives, listening to such emotionally impactful words can really bring tears to everyone's eyes or at least an emotional reaction.

Koreeda, once again, deals with the theme of a found family, while also commenting on important and quite devastating social issues like human trafficking, abuse of underage children, adoptions, birth and of course with the Baby Box itself, an actual box that people abandon their children in for a variety of reasons.

This film is not perfect and I would dare say that it feels more like it has been inspired by Koreeda rather than being filmed by him, but nonetheless it is worth the watch. It is slow paced, character driven, symbolism heavy and as you have understood not for everyone, but I think it is worth a chance just for that one scene that was devastatingly beautiful.