Just an opinion:
The value of FoF exercises lies primarily in a few areas ...
- Recognition of a threat. Shoot vs. Non-Shoot scenarios. Well designed exercises get you broken out of that "it's always a shooting exercise" mindset.
- Getting hit a lot and then learning how NOT to get hit ... survival isn't just a matter of how well you shoot.
- Truly realistic movement and targets, complete with real non-targets.
Airsoft facilitates most of these handily. There is a greater opportunity for people to play that old "you missed me!" game, but everyone learns their lessons anyway.