> our fellow developer deserves to get paid for their clearly awesome work

I agree, but it highlights the many-small-cuts problem

$5 for an eReader, then a mapping app, file manager, photo editor, mail client... the list of developers deserving support is longer than most people can afford. Eventually a choice has to be made to prioritise. For many people that will mean that a less-used category of app can be fulfilled from F-Droid instead of paying for a more-polished one.