I use to preorder much more about 15 years ago. You use to get a demo of the game or some limited collectable. Most demos or trial versions are online now, or you can watch videos of people who get advanced copies. The giveaways now tend to be $10 off if you preorder or some DLC character skin etc.
Maybe if I lived in a rural area that didn't see many copies of games, I would preorder more. I usually only preorder now to get the special financing when I binge buy.
The only thing I could see that absolutely needed a preorder would be the exclusives direct from the manufacturer like NIS or Square Enix, or if you didn't want that spider net security device strangling your collectors edition packaging.