Back in the days I played many freerolls, guess it's a good practice for each new player but ain't that much of a deal for someone who play for many years, but it depends about the money involved in I guess )
I always try to play free tournaments because you have nothing to spend but your time if you have time to play and if you don't, of course it's better to make a deposit or play for money right away and win more money it all depends on how much money you have if you choose to save time and if you don't have enough money you spend a lot of time
Freerolls are perfect to boost your bankroll at the beginning. But I think it's worth to play later as well. There are cases when you just want to relax a bit and play these freerolls and get some free cash (even if that's not that a big winning). Free cash is always good.