Git IS heavily used outside of software engineering.

Marketers and documentation writers use markdown and git for building websites and books.

Data scientists use git for their notebooks.

Operations use git for their deployment scripts.

Git isn't the best for office documents. Revision marking (aka, change tracking), document comparisons, and merging are all available in Office suites. Git isn't really used here because there features predate Git, operated on binary files or complex XML documents (neither of which are conducive to diffs).

Git isn't good for databases or data lakes. The files are huge and typically aren't modified (CSV) or are binary/compressed (Parquet).