The first time I heard this, I assumed the person was off their rocker, but I tried it years ago.
Have you ever noticed that coffee tastes better when your server pours from a height? Try it, but please practice with cold water until you are quite sure you have the method down. Hold the cup and decanter away from your body over the sink.
If you take sugar, have it already in your mug. Unless you enjoy very sweet coffee the pouring action will mix it for you.
If you don’t notice a difference, at least it was free.