I'll explain to you at the level of understanding of a donkey that you apparently have. If you need to pay 10€/h for a lumberjack to cut 10 trees and you only have a manual saw, that takes 5 hours, that is, you spend 50€, but if you have a chainsaw, the lumberjack cuts the 10 trees in 1 hour and you only spend 10€ to achieve the same final result.