In my opinion, it is good for playing poker for fun or slowly build a
bankroll for the micro stake games.
It is definitely, not good practice for buyin tourneys. Maybe, at the last phase of the freerolls, from the last 2-3 tables, you will find similarities. At least, that's the case in most of the freerolls, you rarely find a really high guaranteed freeroll, even there it means nothing to many players.
Some of the CC freerolls can be good, but not all. I have seen plenty 'only freeroll' moves on CC freerols, too. Especially in the weekends. But there are plenty fun players, so it is normal, okay, however this is the reason, why it is not a good way to practice, even sometimes you meet similar players on micro, low levels, too, but you won't pick up the necessary things to reach FTs by playing against them, beating them.