Earlier quoted context omitted.
If you're a mobile app developer, what choice do you have?
On Android you can easily sideload apps. So there is a choice. I understand that 90% of people get their apps exclusively from the Play Store but that is not because Google is evil. Its because people prefer one store were they can find everything: the supermarket model.
By choice, I do not have a Play Store account and wherever possible install apps only from F-Droid. However, there are (rare) times where I want to install a free (as in beer) closed source app. However, the publisher only chooses to make the app available via the Play Store. I would really, really like a direct apk download. I appreciate this approach is not for every end user and some people are scared of the "warning" messages Android displays when installing apps directly. Nonetheless, it would be really nice to have the choice and I don't see it as so much extra effort on the publisher's side.