The full outer product is just the product of multiple tables that all have had the outer product applied to them.
This query is just to show you how many combinations of data are in a full outer product. It does give new meaning to the term "every possible combination" as this now includes combining with the lack of information.
"show every possible combination of people and companies
Finding use cases for the outer product is mostly looking for interesting subsets in this result set.
Do not forget to check the row containing only NULL values at the end of the result set. It is there, never forget that.