No, this is incorrect. Google requires that you use their payment system (which takes 30%) [1]:
> In-store purchases: Developers charging for apps and downloads from Google Play must use Google Play’s payment system.
> In-app purchases: Developers offering products within a game downloaded from Google Play or providing access to game content must use Google Play In-app Billing as the method of payment.
> Developers offering products within another category of app downloaded from Google Play must use Google Play In-app Billing as the method of payment
The only exception they allow is if you're selling physical goods (which is the same as Apple's policy).
What I particularly love is that you didn't actually read the rest of the bullets in the ToS, and you completely ignored my citation of the Kindle app which I intentionally provided as an existence proof.
It's odd that you cut&pasted so many references to IAP, but totally missed the 2nd clause (immediately following the one about physical goods): https://news.ycombinator.com/item?id=10429681
> In-store purchases: Developers charging for apps and downloads from Google Play must use Google Play’s payment system.
> In-app purchases: Developers offering products within a game downloaded from Google Play or providing access to game content must use Google Play In-app Billing as the method of payment.
> Developers offering products within another category of app downloaded from Google Play must use Google Play In-app Billing as the method of payment
The only exception they allow is if you're selling physical goods (which is the same as Apple's policy).
[1]: https://play.google.com/intl/en/about/developer-content-poli...