I wasn't actively aware of this for most of my life until I recently visited a clients office. Buying someone a cup of coffee is an entire thing. There's no free coffee. You have to purchase every single cup. And you first have to walk several minutes to the place where they sell the coffee. It blew my mind. I'm used to drinking one cup after the other without even giving it any thought. Coffee machine right next to me or around the corner. There, coffee incurs friction and cost.
So when you invite someone for a cup of free coffee, this can open doors for you. I'm not kidding. People get all excited when you offer them a coffee break on your dime. And there's levels to it too. There's the regular coffee, and there's the premium one. For the premium you have to walk longer and wait in line until the barista serves you.
It's a key component in office politics when coffee access is regulated.
Why anyone would restrict access to legal stimulants in the office is unclear to me though. Put espresso machines on every desk!