This is what my first thought was, but stated better. Similar to my theory that the magic swords are attempts to replicate the Master Sword; white swords could simply be made of silver (or silver plated), in an attempt to make weapons that are better at dispatching demons.
As a quick historical fact, gilded swords are a thing.
But, we have to remember that gilded swords weren't made from those metals. Those metals like gold, platinum, and silver don't make for very good materials for a sword for several reasons, but it really honestly boils down to them not being tough enough to withstand the stresses of combat, and because of how soft they are, they don't hold an edge particularly well.
The best material to use for a sword is a metal that can handle the stresses of combat, and holds an edge. In other words, it won't break, and remains sharp and pointy.
That's why all gilded swords are still made of good ol' fashioned steel, but then have a decorative layer of gold applied to them.
That's what you see on Maximilian's sword.
It's almost certain that such swords weren't intended for actual combat. For one, they're too pretty to be used in combat, where a sword is going to get damaged from general use, and for two, because of this sword's excellent condition, it probably was never used in real combat.
This also applied to armor, as well.
But, again, judging from the excellent condition, it definitely wasn't used in real combat.
The other thing to also remember, the only people who can afford to have their arms and armor gilded are almost certainly people with money. Those that have cash to throw around, and that's usually high nobles and royalty.
This doesn't discount anything stated in this thread, but to provide some historical basis for the discussion, because gilded swords were and are a thing, as are swords inlaid with gems, gold, and silver.
We like pretty things!
