The story of why someone might seek out and use nulled software like "Inline Related Posts Pro Nulled" can vary:
While the legitimate Inline Related Posts plugin is a powerful tool for increasing page views by automatically inserting related content boxes inside your articles, the "nulled" version is a pirated copy with its license verification removed. The Core Risks of Using Nulled Plugins
Set up features using your current theme.
— You miss critical security patches and compatibility fixes