In addition to speed, wire transfers are not reversible. Which is a feature, but you described it as a bug. People associate wire transfers with large amounts of money because typically the largest transaction they deal with is buying a house. And in buying a house, a wire transfer is used because no one wants an ACH reversal coming through clawing back the funds after selling their house.

Having run a business, 6 figure amounts are routinely moved via ACH. Some banks make it hard for consumers to send money to a random person’s account via ACH, but within the US, it is always possible and is literally how most companies pay their employees.