[sql] Real life example, when to use OUTER / CROSS APPLY in SQL

I have been looking at CROSS / OUTER APPLY with a colleague and we're struggling to find real life examples of where to use them.

I've spent quite a lot of time looking at When should I use Cross Apply over Inner Join? and googling but the main (only) example seems pretty bizarre (using the rowcount from a table to determine how many rows to select from another table).

I thought this scenario may benefit from OUTER APPLY:

Contacts Table (contains 1 record for each contact) Communication Entries Table (can contain n phone, fax, email fro each contact)

But using subqueries, common table expressions, OUTER JOIN with RANK() and OUTER APPLY all seem to perform equally. I'm guessing this means the scenario isn't applicable to APPLY.

Please share some real life examples and help explain the feature!