The advertised point of PG and PBR showcases is to post measurable numbers online, verified by a reputable source. Rule of thumb is "don't showcase until you have something to show" meaning a number (fastball, 60 time, exit velo) that might attract the interest of a college coach, or to verify independently what the travel coach is telling them.
Don't get sucked into the trap of doing these showcases early to "document progress." All colleges care about is where you are when they are recruiting you. If you do them early, you then feel you have to keep doing them to improve the numbers. It's a total trap.
My son, who is at a D3, never did a PG showcase. He did do several PBR showcases, most of which were a waste of money and time. The only one that was useful was the one right after his junior HS season (early May) which had all the local college coaches, juco to D1, attending, which was very useful for 17U recruiting.