Wikipedia (I know, I know) seems to imply it was simply that the die was common, that it was a traditional symbol of an English soldier,
and for identification of friend vs foe:
https://en.wikipedia.org/wiki/Red_coat_(military_uniform):
> However, in the days of the musket (a weapon of limited range and accuracy) and black powder, battle field visibility was quickly obscured by clouds of smoke. Bright colours provided a means of distinguishing friend from foe without significantly adding risk. Furthermore, the vegetable dyes used until the 19th century would fade over time to a pink or ruddy-brown, so on a long campaign in a hot climate the colour was less conspicuous than the modern scarlet shade would be. As formal battles of the time commonly involved deployment in columns and lines, the individual soldier was not likely to be a target by himself.
and
> In his book British Military Uniforms (Hamylyn Publishing Group 1968), the military historian W. Y. Carman traces in considerable detail the slow evolution of red as the English soldier's colour, from the Tudors to the Stuarts. The reasons that emerge are a mixture of financial (cheaper red, russet or crimson dyes), cultural (a growing popular sense that red was the sign of an English soldier),[64] and simple chance (an order of 1594 is that coats "be of such colours as you can best provide").
There is no mention of "dazzle" camouflage or of confounding numbers at all.