Another excellent point, but only applicable to compiled languages (so still not my case).

Just two of many reasons: parallel linting, parallel parsing.

Ah. Silly me. Still, linting/parsing 5000 sloc is almost instantaneous even on my pretty old laptop.

5000 LoC isn't that much.

There are many other reasons why separation is better for humans (separation is organization) but these arguments about parallelism are valid for androids, humanoids and aliens.