By enabling the use of security groups, the actual list of users authorized to access Data Catalog is determined based on ...

By enabling the use of security groups, the actual list of users authorized to access Data Catalog is determined based on the users that are present in the authorized groups at any given time. If this option is selected, the number of Data Catalog billing units will be adjusted based on the number of users who are members of the authorized security groups. This may in turn affect the amount that you are billed for Data Catalog. If you do not want Data Catalog to automatically adjust the billing units, please do not select this option. Instead, please authorize individual user accounts.

Please note that Azure Active Directory distribution groups are not supported for authorizing access to Data Catalog. If you use security groups that include distribution groups as members, the users from the distribution group(s) will not be authorized for access to the Data Catalog.