No greed here. Apple is making this so the argument that they get money for lightning cables is irrelevant. The phone uses lightning. It would be weird if the battery pack used something else.

You can make an argument that Apple should switch their phones to USB-C but they seem to be heading toward a cable-less solution instead. If they were to change to USB-C tons of people would scream that Apple were doing this just to sell new cables. That is exactly what happened when they switched from the 30-pin connector to lightning. I would like to see them switch on the Pro model phones, at least. That market is likely more ready to switch.

Apple makes good money from MFi program, of which lightning connector seems to be a vital cog. The day they shift to USB-C manufacturers will stop paying them for lightning accessories.

Moving to cable-less is a good idea, but these chargers and batteries themselves still need to be plugged into something. I guess that should be USB-C, but USB-C confuses people. Perhaps Apple should move to some kind of solid-state approach like docks built for certain situations (home, travel, car). Abstracting away "plugging in" as much as possible.

Why would the battery pack use USB C if the actual phone doesn't?

Why should they sell USB-C power adapters then? Shouldn't they be lightning adapters?

I’m not understanding the question here. USB-C is used on products where lightning won’t be able to do the job.