Hi, thanks for revewing this change. I am seeing tower:type=communication in tagging practice being primarily used to tag towers that house communication antenna (mobile tower, directional communication antenna etc.). Unfortunately, the OSM wiki documentation is not very specific in defining this tag.
I don't think this tag applies to an airport control tower since the purpose of building this tower is to observe ground (and incoming/outgoing runway) traffic on the airport. I would say that tower:type=observation is more suitable therefor and I've already seen airport traffic control towers being tagged this way. Ideally though I think it would deserve a new tag like tower:type=atc or tower:type=control_tower since it's a distinct tower type constructed for this purpose.
What do you think?