There's also a bit of marketing and psychology involved. A lot of people, especially men, would be embarrassed to say they're "going to see their therapist," but have no problem saying "I'm getting counseling from my coach."
Generally coaching is intended to be forward-looking with an intent to solve a specific problem or question, specifically so as not to encroach on what a therapist does helping someone unpack their baggage from the past.
Reminds me of when Dove tried to sell a "man scrubbing tool" because someone in marketing thought men were too stupid to buy loofahs.