You're going to catch me on this, but I came across an article that referred to how much the Australian Highland troops hated the look of the hat with the kilt.
The dress uniform does look garish, I don't recall seeing any field pictures.
Further interesting note is that it was the ANZACs who changed the way WW1 was fought. The core strategy was based on the most succesful recent model, that is the US Civil War, and forced by Germany's attempt to overwhelm by numbers (I'm keeping it simplistic for time and space reasons.) Anyway, the Anzacs were a volunteer force and offered to unvolunteer if lead into anything more stupid like Gallipoli, they unvolunteered off that spit and into the trenches where they brought their attitude to Canadians, also primarily volunteer. The Canadians offered to also unvolunteer if they didn't have more control. The Canadians were given that control and won the next major battle, and the tide of war changed.

I wouldn't give much credit to the idea of camoflage, except as incidental. That was a later strategy. The wool kilts couldn't handle the type of physical labour that the troops were expected to do while wearing kilts: trench digging, barbed wire, etc. It was a cost effective measure, apron versus new kilt, and not needed on the back because they were not going to sit down. Other pictures will show the apron becoming a proto-UK.

You probably already know the last kilted highland charge of the British Army took place in WW2 during the Dunkirk evacuation by the Camerons (check me here: 4th battalion at Omers). Won the fight. lost the battle (no ammo, fuel, food, anything), won the war. For this the Camerons get to wear the blue hackle (feather) in their headgear. Official reason for discontinuing kilts in battle was fear of gas.