Supplier: <<PierG, for this time, as you are in a hurry, we have sent you a couple of our best designer. They will analyze the stuff with your business experts, will design / code / test the app and deploy a great product in a really short time frame. Are you happy??>>
PierG: <<Sure. But why “for this time?”>>
Supplier <<Because usually we send a business analyst for some days to write a detailed requirements analysis doc. This is input for one of our designers who uses his precious time to make the best architecture for you, and write the Architectural Analysis doc. This doc is sent to our dev team for the coding. Then everything goes to our testing team, that delivers the app after a complete testing.>>
PierG: <<And why? It seems worst: surely more expensive, surely longer, almost surely less good in term of quality>>
Supplier: vaporware + fireworks
Welcome in the magic of Software Development!