I call these "getting paid to poop" apps. They're good for onboarding people to Bitcoin, especially if they have any barriers (mental, financial, systemic, etc.) to buying it.

brxyz

All of these options only earn negligable amounts of money. I think they are nice projects and you can do that for the sake of the project (e.g. use Stacker News because it's a social media) but using them for the sake of earning money is a waste of time