CNAME records

My IT person had used his personal Apple Id to set up my company MDM. He explained it was an oversight - he should have asked me first and he should not have used his personal Apple ID. I accept that explanation but I wondered why he set it up in the first place. I did not want my devices controlled. There was no need. Especially given I had been complaining that I found Google device management policies deployed across my domain. He told me he set up MDM  to allow Microsoft and my apple phones to create a handshake. He argued it was necessary to "harden" my environment.  He said my phone was not being controlled as there was no Intune set up. Given I was not using emails on my phone I queried this reasoning. I never understood why my phone and Microsoft needed to handshake.

I have just read the CNAME records below are only needed for MDM 

enterprisereigistation.windows.net

enterpriseenrollment.manage.microsoft.com

Is there any reason other than MDM for the above CNAME records? Do the above CNAME records allow apps other than Intune to control my iPhone?