Why not slurp mission settings in flyView?

What is the reason for the !_flyView condition in MissionController.cc:2184? What would be the repercussions of removing that condition?

For context: I am trying to create a custom build that adds some non-optional custom commands to the settings. The result is incorrect sequence numbers in FlyView. Removing this condition seems to make it work, but I don’t want to disrupt anything I don’t fully understand.