Kotario
Having gold coins is more than just a problem with the economy and inflation. He has no source of income for such an amount. The moment he brought it out against some legitimate authority, an investigation into his means of acquiring it can easily occur. Not to mention that if it leaks that someone without much standing has such money, the thief that will follow him will be risky.
Don't get why people keep saying that Mc can't cast with a spear. Spear is obviously better weapon due to range advantage. Mc is a mage in the end and sword requires one to be close to the enemy. Besides why Mc needs even need to have one hand free? MC only points with finger and casts spell in his mind. He can do the same with spear.