It's about the overturning of the original decision. Agar wasn't actually given out initially, the umpire went upstairs to make the decision. Root WAS given out and the review was used by the batting team. There needs to be a reason to overturn the original decision in that circumstance. It is also what made Trott's dismissal at TB so appalling as it was a decision that was wrongly overturned.As to whether that ball hit Root's pad or bat first, the video must be at least AS inconclusive as the Agar stumping one, when they decided the principle of 'benefit of the (smallest) doubt' still applied. Inconsistent.