Someone said :
Is milk now unhealthy?
No. The sugar is unhealthy, not the milk.
But putting milk (and/or sugar) in coffee means you do not really like coffee, just its flavor.
And it also means you are more likely to drink more of the stuff.
Also the question was about health benefits of coffee, which should exclude discussions about how milk-coffee is a good incentive for middle-aged women to take more milk in their diet.
So the question is, as stated, about coffee benefits, as coffee goes, as such.
(Note that non-dairy creamers are, like added sugar, less-healthy)