You do not need to participate in a GS1 data pool, however, there are several benefits:
sync your product data in one place, at once, across multiple trading partners/distributors
follow a global standard for data accuracy and quality
significantly reduce time to update product info across multiple trading partners
With a GS1 certified data pool
Without a GS1 certified data pool
When you need a data pool
A growing number of distributors/retailers are requiring that you send your data via Global Data Synchronization Network (through a data pool). In cases like these, it'll be necessary to partner with a data pool provider to get your product information into their systems.
While this might initially seem unnecessary, the net benefit far outweighs any negatives. Distributors and retailers can guarantee they're receiving standardized product information, and suppliers can have a central repository to update their data for all of their trading partners in a single place.