A favorite is a link to a rule or data instance. Use a favorite to quickly find items while working in Designer Studio or the Case Manager portal.
You can create favorites that are visible to your operator exclusively, another operator, or all operators within a specified access group.
A delegated rule is visible to a specified access group. Rule delegation facilitates rule management outside of the development environment.
A delegated rule can be a paragraph, decision table, data type, correspondence, map value, or data type.
Till Pega 7.2.1:
By creating a favorite, you can delegate rules to other users and bring less-technical stakeholders closer to your application development. But it is recommended to use delegate rules.
From Pega 7.2.2 onwards:
You can no longer delegate ruels using favorites, you can use the pyCMDelegatedRules harness in the Case Manager portal to view rules that were previously delegated using the Add to favorites action.