No pain, no gain...

Soviet Union's 1930s Attorney General Andrey Januarievich Vyshinskiy, informally known as Andrey Jaguarevich has put forth a proposition that the suspect's admission of guilt is the ultimate and sufficient proof of any crime. Therefore, once confession is obtained, there's no need for any more evidence. So who needs expensive investigations system, peoples money can be saved by just forcing someone (actually, anyone) to confess!