The rule of thumb: Those with the prettiest uniforms lose the war.
Recall how fabulous those Nazi uniforms are in all the movies? Who can forget the picture of Lee in his finest gold braid surrendering to Grant in his private’s uniform with General shoulder straps dirt? how about the Redcoats surrendering to General Washington at Yorktown?
However, I take issue with your analysis of Confederate uniforms. The Confederates were so poor that half of them were wearing captured Yankee uniforms. The idea of Confederate gray is largely a misnomer, many of them had butternut as a result of home weaving. General Lee put on his best uniform which he rarely wore to maintain the dignity of his army while he alone underwent the indignity of the surrender, an unavoidable but honorable act forced upon them by circumstance which all the efforts of duty and honor could not avoid. Upon learning that he was surrounded with no hope of reinforcements, that his military situation was hopeless, Lee remarked, "Then there is nothing for it but I must go to General Grant and surrender and I would rather die a thousand deaths." With that action he performed his last duty as a soldier and picked up his duties as a citizen of the Federal Republic which he served faithfully until his death.