I think that is where we differ. When there are plentiful E cores, there would be no need to preempt the preferred cores. We could finally have dedicated cores to our important programs with no* context switching, no preemption, etc. of those important tasks.
* Yes, gdansk, there would still be context switching of the unimportant tasks on unimportant cores.
"Usually" is not sufficient in my experience. I see all kinds of stutters and delays when background tasks kick in. Maybe it is fine with your tasks. But certainly not for me.