How does Adaptive Sampling works? On what criteria will this function adapt its number of samples?... Is there a particular situation where you could take advantage of this option ?
I usualy set up the min and max sampling value without knowing their coherence.
With adaptive sampling Cycles automatically reduces the number of samples in areas that have little noise, for faster rendering and more even noise distribution.
More info here: https://docs.blender.org/manual/en/latest/render/cycles/render_settings/sampling.html