That laughing gagmeister George Bernard Shaw wrote that it is impossible for an Englishman to open his mouth without making some other Englishman hate or despise him.
That goes double for copy.
It's so, so easy to get the tone and the tack completely wrong. Stunning your audience into a stupor by banging on and on. Missing the major selling point because you think everyone already knows it.
So to avoid that, we get our professional vowel and adjective herders to do the job. The end results speak for themselves.