I have called this out in the past. The question I had back was "when does this matter"? That is, when does a client actually do a lookup for the domain? My answer is paraphrased below but I would be interested to hear other opinions. Every session with a domain starts with a DNS lookup. You can’t talk to a domain controller without doing a DNS lookup to find the IP address of a domain controller first. Now Windows systems are pretty smart about this – the first thing a computer does is call dsgetsite and store the site name, and users will automatically talk to a DC in the local site when they log on so that’s pretty good, but if you are not a Windows client (like a Mac) or say an Azure joined client, it isn’t so clear cut. So basically anything that goes to find a domain controller or domain using DNS is getting a degraded service. From here, it is basically zero RTT to a local DC, but eighty-five milliseconds to the DC at another site across a WAN link. That isn’t a big number but it is not trivial if you start adding it up. Why would I not want to fix that?
Microsoft