SQL Planner uses sysadmin credential to show greater insight about SQL Server root-cause of slowness , issues , Errors without this it would be very much limited to certain alerts only and its basic metric report. 

Here is details, Where SQL Server SysAdmin user Credential are used within SQL Planner : 
1)	Retrieve SQL Serve Agent Job Execution Details : A procedure in SQL Server under msdb database “sp_help_jobhistory_full” is executed to fetch Agent Job Duration , execution status and is also used in Alert when any Job Fails – The job could be of following but not limited : 
a)	Backup Job,
b)	Index maintenance,
c)	Application Related etc.
2)	Retrieve SQL Server Error Log information: A procedure in SQL Server under mssqlsystemresource database “xp_readerrorlog” is executed to know 
a)	several critical errors , 
b)	warnings , 
c)	errors , 
d)	disk latency IO errors, 
e)	cluster failover events etc 
which is used in dashboard with detailed information and used in sending Alerts.

3)	Retrieve OS Disk space details : SQL Planner hit a procedure xp_cmdshell used to to run Powershell script to extract Disk storage details and is used in Disk Storage Dashboard and used to Alert when low free space detected.

4)	Deadlock, Blocking, Expensive Queries, Waits related Extended Events : SQL Planner creates 3 Extended event to capture Deadlock, Blocking , Expensive Queries & Procedure , Waits (Finding Where Session are waiting). This gives user exact reason about the issues and slowness root-cause with most granular level including parameter details. Which is not possible in other Traditional Monitoring solution.
5)	SQL Server Auditing
 

However  you can trust SQL Planner product - is very much trustworthy, reliable and Many Org DBA has experienced it since last 3 years of usage in Large Org servers and would insist to use SQL Planner fully functional mode and consider it as your own Powerful automated DBA ! 
