Teams Rooms - Account set up?

I'm reading through the documentation but still not sure what way to set up my accounts.  Here's my scenario:

We are hosted online using Microsoft 365 Business so we have Intune, Exchange Online etc. but we do have on premises Active Directory synced to Azure AD.  However, we currently only sync users, not devices.

In the docs, they say "Decide whether you'll join MS Teams Rooms devices to your domain, and how to manage and configure local accounts".  What are the pros and cons of having the devices joined to the domain?  Do I create an OU for the users and for the devices?

Any tips on what accounts create locally, what accounts to create online, and how to configure them?

If I already have a resource account for the meeting room, should I use that or create new?