This one:
Nelson’s Illustrated Guide to Religions: A Comprehensive Introduction to the Religions of the World | Logos Bible Software
is an abridged version of that one:
Religions A to Z | Logos Bible Software
I personally don't mind since I got both of them at a steep discount when they were on sale.
However, duplicate content is generally slightly annoying, and offering the abridged resource for a much higher price than the full resource is not quite customer-friendly (although I assume this isn't done on purpose...)