To train starting hands, sure.
To train bet patterns, proper bluffs, ranges according to bets, absolutely not. At least until you're late/deep, there will be many surprises. You're going to have to pay extra attention to people in freerolls, in my humble opinion. I suppose in that same sense, its great for discipline training, and paying enough attention to gauge their strength.
Feel free to play proper poker, especially when you feel like the player has some game knowledge, but don't be surprised by the many surprises waiting in freerolls or super-micros.
Don't fall into the trap of chasing rainbows after you just seen a fish win, its a tournament, play your ABC's until you learn your XYZ's.
If you're short, respect the strength of your hand, and judge their bets according to your game knowledge of them.