Office 365 does not come with built-in end-to-end service quality monitoring. Office 365 is only able to tell you the status of the service inside the Microsoft datacenter. Therefore, you have a blind spot on everything in-between your end-users and the Microsoft cloud.
To understand the service quality, you are delivering to your sites and business lines, you need something that tests it continuously from where your users are located.
GSX Robot Users have been designed to do this. Contrary to any other application performance monitoring tool, they perform synthetic transaction on Microsoft Exchange, SharePoint, OneDrive, Teams and Skype actions using Microsoft rich clients while also testing the network conditions.