What's Microsoft Intune used to do?

Another question is: What are the benefits to Intune?

Benefits: Microsoft Intune allows you to keep your employees safe while allowing them to be productive. You can create policies that control who has access to your corporate data using Office 365 mobile app administration. Microsoft Intune gives you flexibility and control to secure your data regardless of where it is stored.

The next question is: What devices does Intune support?" Devices which don't allow Samsung Knox activation can be enrolled as standard Google Android devices.

Supported Samsung Knox Standard devices.

Herein, do I need Microsoft Intune?

You will need to subscribe to Microsoft Intune Enterprise Mobility Suite or Microsoft 365. You can manage devices with the Intune admin console if Intune is used by itself. Devices you can manage. Cloud-based management of iOS, Android, or Windows devices

Microsoft Intune is it included in Office 365?

TLDR: Intune is included in all "Microsoft 365” variants. No "Office 365" bundle includes Intune. Intune is also available as a standalone purchase or as part the EMS-suite. Microsoft 365 includes Intune in the Enterprise Mobility + Security Suite.