Intune - Hybrid Active Directory with Autopilot

Hi,

I'm started to make some tests on Intune, but I had some struggles to register machines and also to understand some what the system does in background.

I follow the steps from Microsoft page (Link) and I think there is everything setup correctly. I choose this method because we have Active Directory on-premise that is synchronize with Azure AD, so this is an Hybrid Active Directory.

Also I setup Intune connector to synchronize all machines that we had register on our Active Directory (on-premise) and after that I was able to see all my machines.

My first doubt is something related with this (probably). Once we've our machines register in our Active Directory (on-premise) and they are synchronized with Azure AD, why do I need to create a Organization Unit (OU) in our Active Directory (on-premise) with Delegation Control?

Another question that I have is about Autopilot Deployment. I run the script "Get-WindowsAutoPilotInfo" on my machine to import it on Intune AutoPilot (that was imported successfully) after the import I check the Azure devices and my machine was duplicated, as you can see on the screenshoot:

The differences on the screenshoot is the "Hybrid Azure AD Joined" that is the synchronization from Intune connector and the "Azure AD Joined" is from AutoPilot import. I supose that second register is because I created a Device Configuration Profile (like as said on the link that I follow), see the screenshoot:

Do I really need this profile, once I already have the machine registered on Azure AD?

Thank you.