Was the Jewel of Life really responsible for making Michina fertile again?

Does anyone besides me wonder whether in 'Arceus and the Jewel of Life', that the Jewel truly was responsible for making the Michina wasteland green and fertile once more when Arceus entrusted it to Damos? I don't know about everyone else, but I think that in the end of the movie, Arceus sort of seems to imply that the Jewel of Life was NOT in fact responsible for it, that is was merely a means to give the residents of Michina confidence in their own ability to restore the land; a kind of placebo effect, one might say.

Arceus: "This isn't my doing. Your ancestors dedicated their entire lives to cultivating and restoring this land. This place was brought back to life by the efforts of people and Pokemon alike."

Sheena (smiles comprehendingly): "I understand."


Am I reading too far into this? Does anyone have an opinion?