I can only echo pretty much what others have been saying here already. You can certainly win off of free spins from time to time but the likelihood of actually winning something of any sizable amount or winning every often is just not that likely.
Ive won on free spins before in the past but its been quite some time and I never had won anything of much.
Free spins are still good though since they can be a source of small profits somehow, but if you wish for significant amount of profits, you will not likely to experience it from free spins. You have to deposit a good amount of fiat so you can bet big and win big. That is most likely possible with high rollers since they have high bankroll ready to finance their gambling bets. However, I have not made significant gains from free spins, only small winnings that I almost forgot how much it is.