Where the money comes from
Every reward on an earning site starts with a company that wants something: a visit to its page, a new app user, an answered survey. It pays a network, the network pays the site, and the site shares that income with the person who did the work. When you know this, it is easy to judge an offer. A real task has a clear advertiser and a clear action. If a site asks you for money before it pays you, that chain does not exist.