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What is the point of low end discrete gpu in laptops? [closed]

i have an Lenovo g40-80, which has an i5-5200u cpu and an amd r5 m330 gpu. To my surprise when i checked the performance of the igpu on 5200u and the m330 gpu, they have similar performance, what is the point of that low end discrete gpu other than using more electricity than the igpu?

another one would have i7-7500u with r7 m440 gpu, which the gpu performs worse than the igpu on the 7500u cpu, it seems to me that low end discrete gpu on laptop are pointless other than increasing the price.