I always thought the point of a benchmark is to show what a device is capable.
So if the "phone does indeed let its GPU run at a higher frequency when particular benchmark software is running",
Its just showing what its capable of.
Though I would definitely want to run benchmarks the whole day and see what happens.
Its about time we use our phone battery power for productive work instead of wasting it in a grossly inefficient piece of hardware: the power amplifier.