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.
Free bets are definitely not a complete waste of time. I have personally won decent profits through free bets and withdrew them successfully from some sites though the requirements need to be satisfied.
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.
They aren't a complete waste of time in my experience with them. You need a lot of luck basically to satisfy the requirements related to free bets. The requirements vary from site to site basically.
Some sites like FJ have additional issues such as high minimum withdrawal amount etc making it even more complicated.