Steven Lance Rocker I may not be having a full understanding of your business model. Hence, I cannot comment much. In general, the use cases for plagiarism go anywhere there’s a thesis, paper publication etc. you name it.
Imagine, I have a written material received from my co-worker that I need to publish on my paper, I want to check for plagiarism and don’t want to publish the copied materials if any from outside world. Or imagine, I am a student and want to check for plagiarism before publishing or submitting for final review, then I do have to follow necessary checks.
Summary - Plagarism and Citation are two different aspects and need to be considered independenly.