I think "loser breaks" is excellent for league team practice.
We did this with one of my teams before matches. We had 5 players. Some would be shooting good and others not so good. So we would play for about an hour before the match.
The guy who was shooting the worst got the most time on the table. The guy who was shooting the best got the least amount of time on the table. The player who was shooting the worst would improve quite a bit. This helped us to win many matches.
On other league teams I've been on, we practice with winner breaks. And there are players who can run the table from the get go. So a lesser skilled player will get up to the table, the better player will win the lag, then breaks and runs out. The lesser skilled player gets NO practice.
This is dumb if you ask me. Everybody should be helping that lesser skilled player to play better and we should give them the most amount of time at the table. Also if someone does run the table, let the loser shoot in the remaining balls before starting another game. They don't improve sitting in the chair and watching!