Official Reuters comments regarding this are here.
Reuters Issues a Worldwide Ban on RAW Photos
Basically...improved speed, lower workflow for photographers, a more "realistic" interpretation of scenes, FASTER turnaround from shooting to delivery, less chance for
artistic license or unethical shot toning/editing/massive corrections that would alter the reality of the scenes, and so on.
I recall a few basic, rather general details from an incident I read about here in the USA a few years back, when a photographer shot a political rally, and very significantly ALTERED the weather in the image he submitted. I can't recall if he made a cloudy day into a bright day, or took a dark, gloomy day and lightened it up significantly, but it was one of those two basic things: materially mis-representing the weather at a scene, to a very significant degree. As I recall, the paper ran the photo, and then immediately editor started receiving phone calls from people who had been at the event, stating emphatically that the weather was the exact opposite of the way it had been shown in the newspaper's image. As I recall, the photographer was let go, for basically, deliberately "faking" a reality that had been seen by thousands of people in the metro area; the undertone was alleged or thought to be trying to cast the speaking politician in a negative light. I wish I had the exact details of this incident handy.