You get reversion with bigger cams but that's only one reason.
The maf is less responsive due to the distance from throttle body as it measures air flow where map is instant.
Mafless tune is better wether stock or modified its way more responsive and just goes better.
I tune these so its not just because some other person said so its from experience.
The one issue is fueling is a lot harder to get right but if the tuner knows their ****
it wont be an issue.
People keep saying keep the maf on a stock engine but cant say exactly why.
Some tuners keep the maf as its just easier in comparison to re mapping the virtual ve table.
Then there are other fueling tables that come into play like PE and dynamics.
Maf is just easier for them.