When someone clips a family member's obit and sends it to a relative and then–even 20 years later–that relative's daughter starts family genealogy and finds great-aunt Susie's obit ... she doesn't simply read:
Smith died last Thursday at her lake
Services Saturday, 10am at Christ Church"
WHEN was Thursday?
WHICH Christ Church?
...and, after a few minutes puzzling, gives up and tosses out the obit!
Instead, imagine a code tucked into the obit, such as "A10023N1998FB18" (fictitious, example only). She asks a librarian, genealogist or historian about it. She's told, "Oh, that's the Publisher's Genealogical Coding Service code! Here, let me look that up. That obit was from the Buffalo, NY News; published the 18th of February, 1998!"
What a treasure trove of information from one small code!