If you are finishing in around 100th-500th place out of 5,000-6,000 players in a freeroll then it is good experience.
Sure, you're not going to set the world on fire with the amount of cash you are winning but it certainly is very valuable practice for later in the day.
If you ask me, it is important to approach a freeroll with the right attitude. That is, with the intention to play your best game and do the best you can, rather than to just blast off as soon as possible.
Not the best idea for inexperienced players to be diving into the deep end, freerolls are a great way around that and to start getting comfortable with new strategies and styles of play.