[ufo]

Tables being dual purpose is fine. The real problem is that assigning nil deletes the table field. Unfortunately, fixing that now would cause Python3 levels of breakage.

[90s_dev]

I've never had an issue with =nil being delete. What problem does it cause?

[ufo]

If you accidentally store nil in an array it creates "holes" inside an array, which breaks the length (#) of the array.