It's not about paying Google. People can buy gift cards with cash and do that; that's not the problem, especially not for commercial use. It's everything else that they're imposing or could impose on a whim and whose device it is they're putting restrictions on.
Last I heard, Google doesn't employ law enforcement. I can auth to the people we vote for and any laws they make such as bank KYC against specific criminal activity. Nobody gets scammed via an apk when it's infinitely easier to put up a webpage or socialmedia profile
I'm actually working on a project that targets dual screen android handhelds. It will be kickstarted with a free demo. Android side-loading is the ONLY way to deliver that application to backers. I'll need to go thru Google's developer surveillance process (but u right, I already was going to because the demo and the full release will also be in the Play store.)
Oh and to answer your question about B2B iPhone apps, YES. Not my department at my last job but i know the application needed to go thru apple approval process and app store distribution. And it was difficult to keep in sync with a back-end on its own release schedule. That's why I'm pretty sure everything ended up getting turned into some sort of web view.