Like others said, it depends on why you are playing league.
Its not going to be the highest level of play, but you'll likely have plenty of good competition. It can be a long evening, but depending on the scenario, you might get a lot of practice against different opponents, which is different than solo practice.
The social aspect is self explanatory. Some leagues are great this way (ours is), while I understand thats not always the case everywhere. I truly enjoy seeing my friends on pool night, friends that I hadnt met till I (and they) joined the league. Not everyone is into this social aspect, I grant you.
Why not do the home practice AND league?
Good luck to you.