Task Scheduler and Windows Server OS

We have 6 robots currently in our org. When we consulted one of the UiPath representatives during the developer conference, he suggested that we should be going to Orchestrator once we reach the 10 robots mark. 4 of our robots run with the windows task scheduler option. These are in the cloud. 5th and 6th are windows server OS machines hosted on-premise. Here when we try the windows task scheduler, it runs but robot does not take the session and logs you out. Also when we close the session, the automation breaks.

I know UiPath does not support the task scheduler but is there any reason for such behavior.?

Also if UiPath does not support task scheduler, Why do they suggest that minimum 10 bots qualify for an orchestrator?

@loginerror can you please help here as we are having an unforeseen situation due to ongoing business scenario with virus outbreak