As a parent who doesn't coach I have a different perspective on pitch speed.
To me it's like hitting in this way. I really don't need to know how fast he is throwing or what his batting average is to know how well or poorly he is doing.
My son is a position player and part time pitcher. He's 16.
In all the years he has played, the only time I knew his batting average was when he was 8 and the coach put a package together for each kid at the year end pizza party. And the first time I ever heard his in-game pitch speed was this past fall. The coach told him, while we were walking out of the park, that he was throwing well and hit xx mph and should work on his pitching more.
I can tell without all the stats whether he is throwing well or hitting well. He knows also, and so does anyone watching. That goes for all kids.
Does his swing look good? Is he driving the ball? Does his pitch have pop? Is he working hard in the field? Is he contributing? That's the big question. These questions I can answer without the stats.
When someone asks me how hard he throws I tell them I don't know the number but he seemed to be throwing pretty hard or he seemed out of sync. Would I like to hear that he hit a certain milestone MPH? Yes, if someone wants to tell me. But I don't see what good it does me to know. Is a scout going to ask me how hard he throws? I doubt it. When someone needs to know how fast he throws, his batting average, or how many HR's he hit he will find out for himself or ask the appropriate person.