Why did Allah Almighty say in Surah Al Imran, verse 148: "So Allah gave them the reward of this world and the good reward of the Hereafter"?

Allah Almighty describes the reward of the Hereafter as "Al-Husna" (the best/most beautiful) to encourage striving for it and to draw attention to its magnificence, and that the reward of this world cannot be compared to it due to its impermanence and its mixture with harms, while the reward of the Hereafter is Paradise and everlasting bliss.