The true story is the only benefit is consistency. The stock tune actually has a bit of ignition correction and timing reduction, especially when heat soaked. (also depends on gas quality, ambient temps, heat soak and other external factors).
100+ octane will reduce almost all instances of timing drop outs after back to back runs, but heat soaking of the intercooler and increase in IAT's is inevitable.
It isn't a power adder. It simply gains back any power that was lost from poor fuel quality.