As with pretty much any staple food. It’s used as a filler. The reason you might not understand is that it can be expensive to eat only meat, veggies, etc. A cheap staple like rice, noodles, or bread is a good way not to die of starvation or at the least keep some money in your pocket.
If a staple food isn’t part of your daily diet, that speaks a bit of privilege on your economic position.
Also I enjoy rice. It’s neutral tasting but with a tiny bit of seasoning it’s good.
Yea I agree $40k is a bit disingenuous. But the cost of a car is more than the car itself. It’s better to view it as a ongoing expense of fuel, insurance, maintenance, etc. AAA estimates between 7-10k a year. https://www.aaa.com/autorepair/articles/average-annual-cost-of-new-vehicle-ownership