At the risk of this thread taking a detour into the "size and projectability" realm which is not my intent, nor Midatlanicdad's either I'm sure, I will accommodate. Son is an RHP and was an athletic 6-5 or 6-6, 175, summer of rising soph year but was throwing only about 80-82 when he first went to HF. So, he stood out, like literally due to size, not for his velo or pitchability.
So when OP was asking if a rising Jr. should go, my reply was "if you believe your kid can stand out as a projectable player," especially as a pitcher, it can be worth the effort, and you can establish a great foundation for future recruitment.
But moral of my son's story is even though he went to HF (and PG events and other showcases) on the early side at age 15 and 82mph, in the end it really didn't "move the needle" in his recruitment time table. Yeah, he got visits, got attention but still did not get his first offer until age 17 and 88mph. Now, if he was 15 and 88? Not sure he'd have even gone to HF?
I'd be the first to admit, showing up earlier to events like HF only got him early exposure. And yes, the coach and school he ended up committing to did see him that first summer at age 15. But do I think son could have just done HF this past summer and still be committed to same school he is now? Yes. No doubt.
However, those two years son was able to connect on multiple occasions with that coach who apologized for not having time for son at age 15 at HF, and thru camps and other avenues, a relationship was built over two years that son was all the more confidant about when offer was finally made.