For a young person, you have managed to solve one of the great mysteries of this civilization. IT'S ALL ABOUT MONEY!!
Look all around you, ads, jobs, promotions, burglaries / theft, drugs, prostitution, gambling / betting, real estate, taxes, manufacturing, software / operating system updates...etc....etc.,
ad infinitum.
Money is the grease that helps the wheel of society turn.
Have a nice Christmas in spite of the money thing. We also take credit / debit cards. LOL!