You can gain a lot from freerolls by learning how to gain information from opponents around you based on what action they are creating, and other tells
and what not. It's helping your reading ability. Also, you can learn how you can create a table image. You can practice looking at your cards and maintaining the same posture. Practice how you place bets. Practice calculating a pot. Practice sustaining your stack.
These are all things that are individual skills, and you don't necessarily need to be surrounded by worthy opposition to improve these aspects of the game.