The study and results are impressive and cover many of the concerns often mentions however they are not comprehensive(and not claimed to be by the author so no slight) You already mentioned speed to first shot. The paper also doesn't mention or address with testing the iron sight method of target focus with sight alignment nor laser use for target focus and alternate body positioning factors. It is a great study for sure but more needs to be considered and addressed or tested for a fuller picture. The paper often cites the need to change focus between target and front sight and considers the factors of time and difficulty in this focus change especially under stress. A target focus use of iron sights may have an effect on speed,accuracy and ease or ability to perform. Rob Leatham and Doug Koenig both mention using this technique sometimes out to 25 yards.
Alternate/down/injured shooting positions is another factor that may be faster or slower to get weapon alignment using MRDS or iron sights. Nothing is perfect so it comes down to knowing and weighing the strengths and weaknesses of each and making a decision personally or as an agency.