Sounds good, there are not many casinos that provide exclusive bitcointalk contests/challenges at the moment and maybe in the near future.
If you can come at the right time for the challenges then it may boost people awareness about your site but of course you need to provide attractive challenges so many users will be attracted to participate.
Combination between free giveaways and challenges where users need to spend their own money in order to participate will be better ofc.
Well, wish the best luck for your project and hopefully it will be officially launched soon.