Because sometimes you cannot look things up on the web. Imagine a sales management app that calculates the discount on a sale. You cannot google that to find the answer. But if you write the app and it returns a discount of 10,000,000$ on an order of 100$ then that’s probably wrong.
What he is really saying is that you will write much better programs if you understand the problem domain, ie you understand what its supposed to do
Imagine being asked to write a program that computes the frunk ratio of the splidge grouters given that each froop has 12 enzags. Is 42 a good answer? Many times I have seen devs in this situation – they have 0 idea of what the program is actually doing and so cant tell if they are writing junk
solved The importance of estimation [closed]