Contrary to your suggestion, I would argue that most businesses do not want to predatorily extract money from unwilling customers. It's typically the old, calcified businesses that do not innovate (gyms, cable companies, etc.) that engage in this behavior.
I want more margin so I can hire more engineers and change the world faster.
Google probably sees regulatory pressure writing on the wall, and by doing this they're building evidence that they haven't built a mobile computing monopoly or are backing away from it (insofar as running executions on your customer's devices used to be free in the desktop computing world where two corporations didn't tax all of innovation).
Also, it's a shot against Apple, who is definitely the more egregious of the two.
This is all around good. There might be a company or two that abuse the system, but that's easily dealt with. In an open app ecosystem, you still have measures in place to correct the bad actors.