The fat content of the raw milk produced by cows ranges from about 3.3% up to 5%.

https://en.wikipedia.org/wiki/Fat_content_of_milk

TBH I kinda get the dude who added milk powder to his milk, though. One of my favourite ways to drink coffee is to add instant coffee (the pure coffee variant, no milk powder) to a cup of milk and microwaving it. If you want to add proper coffee and don’t have an espresso machine, I can see milk powder making up the difference.