Free bet is useless. Even if you win, you're unable to withdraw the winning proceeds. So, why waste times to play free bets? Unless you just want to have fun and get acquainted with the platform.
Yeah for most of sportbooks, free bets seems to be hard or sometimes cannot really be withdrawn. Even so, there might still be few which really pays out the winning from these free bets. There are just terms that is needed to be meet before the player be able to get his winnings.
Free bets are promotions which is most of the time a waste of time, unless you'll be able to get it.