My observation has been pretty consistent over the years.
Plants will certainly grow with minimal agitaion and no air diffusers in the plant modules.
Though, the roots that grow are far more flaccid and less vital than those grown in the presence of diffused bubbles and turbulence. This tended to result in:
1) lower essential oil content
2) higher deposition of sediment in grow mods
3) fewer fine root hairs and fish bone type root developement
4)less transpiration and inturn lower plant metabolism
5)necessity for use of nutes at higher concentrations given the reduced nutrient uptake efficiency
6) looser flower development
Assuming none of the above matters, then I would say growing without air diffusers is great.
For anyone who is curious, do the side by side and judge for yourself.
IMO, this debate is remnisent of the rhetorical "I don't need a chiller" discussion.
Seems to me the strongest opinions areoften held by the weakest growers.
I'll take air diffusers all day.