Sales Figures from Seller Central Business Reports
Via the Performance integration the Sellics user will "read" your Seller Central reports in the following section:
Reports > Business Reports > Detail Page Sales and Traffic
Viewing Only Rights of Business Reports
During the integration the Sellics user will be given the necessary "View & Edit" rights to your Business Reports.
As reports cannot actually be edited, the user is basically only given viewing rights and will not be able to change anything in your Seller Central.
You can remove the user or the given rights at any time in your User Permissions.