That's a nice and simplified explanation,
So can you tell us what can be a realistic number of GIvsAA and Light samples, As a example?
Unless you have soft shadows or low angle sun, you can leave LSM at 1, although you need higher LSM if you have Volumes.
2 is a conservative default value.
If you happen to do animation with simple geometry like me, no high IOR refractifity is used and don't have dof or moblur, then 8 passes is already enough, but GI after 8 passes is aweful, so you need to compensate with 64 or 80 AAvsGI.
If you have Carpets, displacements, dof, moblur, then you need more passes and default settings (with LSM 1) do already a great job. So you don't need crazy high GI sampling and there is no reason to go higher then 16.
As you see it is very dependant on what the scene is or what you need.
Refractivity, fine geo, dof, moblur, bad Antialiasing, fireflies from reflectivity combined with detailed normal and bump maps etc... Need many passes
Soft shadows, volumes with much direct light, god rays, low angle sun, Noise in the Direct lighting pass etc... Need more direct light samples, so more LSM
Noise in indirect pass and GI noise, SSS noise, etc... Need more rays casted, so higher AAvsGI
Find out what you scene needs the most and just crush everything else to the bare minimum, without loss in quality after the image has rendered.
But then again we are talking optimisation here, you can just say screw it, corona with adaptivity will manage and let it render on default settings, which are in the golden center of all use cases and adaptivity will do its thing.