Same with the store: why bother selling the food for money? If the value is the same, why doesn’t the store just keep the food and save themselves the trouble?
Well I for one always took issue with the rational consumer model. It is possible that people trade things they value for things they don't, because people do not always act rationally.
By the way, economic concepts are statistics. Arguments are only meaningful on large number of samples or over long period of time.
* The company now has more money for research and development, which will result in the creation of new value.
* Demand has been demonstrably increased (from the moment before the transaction), providing a small but real signal that production should increase. Increased production will result in new value being created.
And so on. This is all on average, of course. Some companies destroy value through incompetence, ignorance, malicious action, or other mechanisms.