Exploratory testing != Litmus Testing/Already Made and Ran Test Cases.
Why are explorers called explorers? Is it because they roam the land in where things are already mapped? Or is it because they map uncharted territory? I would go with the latter. I’m not sure why people confuse exploratory testing parts that already have been explored.
Manual Testing is not a good way to spend doing performance. For repetative work, these things are better handled by automation where things can get closer to a constant. With manual work, there is a greater chance of a delta being due to human error. If there is an error in the performance automation, there’s a greater chance that it will be a consistant error.
There are parts where manual testing is better suited, and there’s parts where automation is better suited. My opinion is that we should use the people and equipment for what they are better suited for rather than take a hammer for a chisel’s work.