It allows creators to keep a public log of their writing sessions (e.g., "Started at wordCount 1.2k, ended at wordCount 2.56").
If you tell me (e.g., on a writing blog, in a software error log, or a specific app), I can give you a more targeted breakdown: Writing platform (e.g., Tumblr, AO3, Wattpad) Software development (e.g., GitHub, a specific text editor) Academic or data context (e.g., corpus linguistics)
While less common, "wordCount 2.56" might also appear in technical logs for:
For readers, seeing a word count in the metadata of a post helps them gauge how much time they need to set aside for reading.