Why does Gilgamesh's casual appearance look different in different routes? In the actual Fate Route (after Saber is summoned) we see Gilgamesh in casual attire when he confronts Saber and Shirou before getting into his golden armour. However, in Unlimited Blade Works and before the start of the Fate Route, his casual attire is different, particularly his hair and that he's not wearing earrings.




(left: Unlimited Blade Works; right: Fate)

Now I can understand that in Unlimited Blade Works the reason he doesn't wear his armour when fighting Shirou in the end is in part due to his ego in thinking he won't need it on someone like Shirou. However, I don't think it's his ego which is the cause of his change in appearance.

So I am wondering, why does Gilgamesh's casual appearance look different in these two routes, considering his Unlimited Blade Works appearance was also seen when he was talking to Sakura?
I never play Fate/stay night until the end but know a little, I think it's more like "he has anything in his vault and willing to wear casual clothes, so let's make him stylish" sort kind of thing. Because as I know, other servants don't even wear "normal casual" clothes as much as Gilgamesh, they pretty much always use their astral dress/clothes which is very(?) strong/sturdy (in the case with Saber's dress that can block certain magical attacks).

As for the reason why Gilgamesh wear casual clothes much, I think it's to emphasize his arrogance, I mean he is a king and think himself the most powerful entity in their universe, and mostly because he is ranged-type because most of the time he just throw whatever in his vault, even his strongest weapon Ea isn't melee-type weapon like Lancer's noble phantasm Gae Bolg: barbed spear that pierces with death or even Caster's Rule Breaker or Assassin's Tsubame Gaeshi.