This is the reason Apple started doing this way back. Sad to see Google follow suit. I guess the bottom line is the bottom line...

I thought this was a Apple only thing and Google doesn't do this. For example, you cannot buy Audible books frim iOS apuo but can from the Android app.

You can, but I don't think you're supposed to direct your users to put their credit card info in, that all needs to be handled somewhere outside the app (with a message like please sign in on our website). Which seems very blatantly anticompetitive to me.

Now that I think of it, Uber has you put your credit card in. I'm not sure why that's allowed

It's allowed because Play Store in-app billing is only required for digital goods & services fulfilled by the app, not physical goods & services fulfilled outside your device. Uber isn't selling you app functionality, they're selling you the physical service of transportation, so they're exempt.

Quote from policy [1]:

Developers offering products within another category of app downloaded on Google Play must use Google Play In-app Billing as the method of payment, except for the following cases:

- Payment is solely for physical products

- Payment is for digital content that may be consumed outside of the app itself (e.g. songs that can be played on other music players).

[1] https://play.google.com/about/monetization-ads/payments/

Oh, what if the donation link added you to a list of contributors to the website. Seems like that would be "digital content that may be consumed outside of the app itself" which might be a workaround. Google might ban it anyway of course

I am sort of annoyed the other replier didn't see the sarcasm here, so I'm going to point it out, and note that it's funny -- seeing the motivation behind a behavior doesn't automatically invalidate it.