Personally, I'm in favor of making the stats open for view. Most of the time, players already know where they rank on their team. This just quantifies it for them. It should also help players and coaches direct the proper attention on areas they need to improve. If some players don't quite grasp their value on the team (high or low), practice and game stats will serve as a reality check.
No real downsides as far as I'm concerned, except for the extra time it will take for coaches to collect and maintain the numbers. And I assume that these would be used most often for travel or national level club teams as opposed to lower level teams. "Three" and "four" level club teams are not likely to have coaching depth to handle this effort. College teams can do this because they have much more coaching support.
If I had a choice of placing my DD on a team with practice stats versus a team without, that would be a no-brainer. Stats every time. BTW, I don't buy in to all the GM2 stuff (and the Cauldron system predates Gold Medal Squared by quite a bit, I believe), but I really like practice stats.
And, as an added bonus, it'll make it easier for coaches to show parents why their DD is playing or not playing. No more arguing: when your kid's numbers improve, you'll see her on the court more. Maybe that helps make up for the extra time it takes to maintain stats.