When to use an integrated filter?
Well, the datasheet shows an example of SD card interfaces, MMC interfaces, etc. I'd suspect these are used in general on fast data lines to control the edge transitions and meet EMI requirments. 

How would you know if you need one? Failing an EMI test would be indicator. 

Keep in mind that datasheet examples and recommendations are not sufficient for a functioning system that works at all the edge cases.