NM: While I kind of agree that the idea that doing good deeds with the intention of earning rewards in the hereafter is a kind of reductive disintegration of morality may aslo seem to be extremely attractive from a philosophical perspective.

however having said that. God almighty while mentioning the rewards of good deeds he intends to address the natural desire for his mercy and blessings. Such humans who realize that they are indigent and needy of His special blessings to even sustain their existence.
Human kind have been informed that if they live a life of goodness , piety, morality etc , they shall not only earn the bliss , love and pleasures of their Merciful Creator - which is indeed the biggest reward for those with a strong faith in him, but shall also provide them with all that their hearts desire and shall grant them unimaginable bounties as a special gift from Him for living in accordance with what he loves of them to do..