High School Coaches are usually Teachers who are volunteering their time or picking up an extra task for a few bucks after school. No School, to my knowledge, hires a bowling coach.
The best Coach at that age is someone who knows how you bowl, and can spot a problem. Just to be able to identify that something has changed, or some habit is causing trouble is good enough for a good younger bowler. My Dad was mine.
A Training Coach is something different. Here, the ability, knowledge of the game and certification qualifies this person to work with you to improve what you do.
Eh? Here, they are recruiting high school bowling coaches in the local bowling newspaper. They are offering USBC backed seminars just to teach those recruits. IIRC Richard Shockley is teaching the next one. Doesn't sound like high school teachers as coaches to me.... Although a teacher probably has to be involved somewhere. And if I heard correctly, they want all the high school coaches to get a minimum of USBC Bronze Coach certification.