best response confirmed by Forrest Hoffman (Regular Contributor)
Solution
It does also say:

Note
These DNS records also apply to Teams, especially in a hybrid Teams and Skype for Business scenario, where certain federation issues could arise.

As I say, plenty of customers don't have them and never had a problem but others have when there's no SRV record. If you also have federated partners who use Skype for Business, then you'd need those records for them to federate with you.
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