I am not sure but is there a way you can verify a free spin? or make sure that it is fair, I think those kind of things were not usually the focus of the gambling site and wouldn't really use 1 BTC just for their free spins I think they have budget for it but really small one and it is impossible for you to win a 1 BTC as they are only a promotion to keep players still playing in their website.
There is no way to verify the result of the Lucky Spin feature. As long as I know it is a free feature for players where players can spin it regularly without any other requirements. For me the huge prize is just a gimmick, this feature has been running for long time but I have never seen/heard someone win the main prize. Sure, no one can complain since it is a free feature. @OP Do not hope too much for something you get for free, if you think it is wasting your time only then stop it.