Group demo is good.
When you don't draft high.
When you don't want to spend a lot of points.
When you are satisfied with an all-star potential.
I use it mostly when I don't have a high draft pick and I am looking for an extra trainee the next season.
It is most fun to train own drafted players.
You get like 19 players. Mostly 7 of 8 are worth to interview. star rating 4,5 balls.
Out of this normally 3,4 have like 3 or more potential balls.
So for around 26 scouting points, you get mostly a nice trainee, which in a few seasons can be a nice back-up.
Only in the dark, we succeed!