Driver assistance systems for example. I don't want to pay for those features, but if I don't get them when I configure the car it's going to be much harder to sell the car a few years later. If those features can be activated later on, I won't lose money when I'll sell my car. So it reduces the initial cost of the car and then I also get a better resale value.
It’s already priced in. You’re just paying more for the features you aren’t using.
You enable them as an upgrade, for additional fee. Just like you update maps on rarely used in-car navigation system.