wondering if those who rated it 10 can give explanation

I agree, there's nothing particularly unique about this film.

The same story has been told before, and arguably more effectively.

But, the key difference that makes this film noteworthy is that it's representative of the African population in Martinique. For me such stories - similar though they may be - help to connect the historical dots between displaced Africans throughout the West.

I look at the faces of the characters in this film and can't help but be reminded of my own grandmother's face, or my uncle's face, etc.

Yes, the story is a familiar one, but familiar in a touching way.

That's why I gave it a "10".

I'm not sure why if on some the level the movie didn't engage you'd care why others enjoyed it. Nonetheless, for me, the movie touched upon universal themes. Those being the importance of education as a means to overcome the misery of abject poverty. Also the self sacrificing nature of the Grandmother. She literally worked herself to death in the sugar cane fields to give her grandson a better life. If you didn't see the movie through the central character's eyes, then I guess you missed it altogether.