No, but there are advantages of building 2001 coven. First, having a fully equipped Coven will increase your strength in fights. Next it's good to keep in mind that to complete all of the mission volumes in the game, you will need 2001 coven.
*Don't forget that you're awarded 5 Minions at each level up, and that Minions add to your total Coven. You can choose to play without any real live players in your coven... although without 10 you are at a slight disadvantage by not being able to collect and offer rage and energy to and from them daily.
Besides, it's fun to have some players to interact with, unless of course you don't like talking to players. No worries, we have you covered there too!