on a mass airflow sensor the honeycomb grille helps a lot because the sensor is only sensing a very small slice of the airflow in the center of the sensor, but it needs to be a good actual representation of the total airflow, the honeycomb is an attempt to force the airflow to be uniform throughout the whole circumference, making the very small slice that's being measured representative of the total airflow.
like you said, after a curve is particularly problematic because the bulk of the airflow will naturally favor the inside of the curve and then favor the side rather than being laminar throughout the whole circumference.
to me the place something like that may be slightly beneficial would be at the air inlet when the coil is right up to the air inlet. for example, I think it would help flavor a little if instead of one single round hole to feed the coil, if there were many tiny holes, or in effect a honeycomb to distribute even airflow across the whole coil, I think that would give better flavor extraction. going from just round holes to slotted hole is a step in the right direction. I've seen some atties with multiple holes swiss cheesed into the side of the atty but these are generally way too large, more suited to cloud chaser setups.
really I don't think it would make much difference at all on most atty setups, truth is that most atty setups are only drawing prime vapor fresh off the coil from only a portion of the coil anyway. for example most dripper setups are only extracting the freshest "prime" vapor from the outside face of the coil, everything else becomes secondary stagnant vapor and can add harshness if reintroduced into the vapor extraction. that's why when you raise a coil throat hit and harshness will increase, it's not because the vapor under the coil is different, it's because raising it allows a bit of flow under the coil which in turn causes turbulence and a raise in pressure in the stagnant pockets which reintroduces more stagnant vapor from the pockets in the chamber to the extracted stream. these stagnant pockets would remain less disturbed so less reintroduced to the vapor stream if the coil was lower and the airflow just goes mostly over the coil straight to the driptip. the ratio of "prime" vapor compared to secondary stagnant vapor in the vapor stream directly determines the taste and vape quality. ever try to vape when the coil is opposite the air inlet? harsh high throathit and not great flavor, this is because you are getting pretty much all stgnant aftervapor and no prime vapor at all.
this is why a bottom air inlet to the coil is so good when set up right, IE; coil mostly centered over the airholes so airflow is on both sides of the coil. more of the whole coil gets extracted directly and the vapor that makes it into the more stagnant central and side pockets that become stagnant doesn't have as much chance to reintroduce itself to the vapor stream, but another key thing is that there is much less of this secondary stagnant vapor generated to begin with because the vapor extraction fro the coil is much more complete, the kayfuns were the first atty I've seen to use this strategy
some of the better tasting side air inlet drippers use a domed bellmouth at the top for a more smooth transition to the low pressure high velocity vapor flow in the driptip . the bellmouth causes less turbulence in the chamber overall which gives a more laminar flow from the coil to the driptip which in turn introduces less of the stagnant aftervapor back to the vapor stream, hence better flavor...
vapor quality and taste is def a science, and being so means it can be figured out. I've been trying to figure it out for the longest time now and I think I have a good grasp on whats happening and why but truth is there's no way to validate and confirm these hypothesis to be actual. I chose to believe them to the point that worse case even if it's not factual as to what's actually happening it's at least illustrative and representative of whats actually happening for the most part, I think