Okay, so there are already a couple gambling sites that work off this same concept (guessing digits of your transaction ID) as well as other options of gambling, so I guess it's better to check out those others before using Bitcoin Betting.
I would like to know about those gambling sites that work on this same concept. I am not aware of any. Please note that, this is not guessing digits of your transaction ID. Transaction ID (or Hash) can be created offline and hence can not be used as an unpredictable string. This is about guessing the last digit of the block hash which would include your transaction ID. This is something absolutely new as far as my gambling experience is concerned. If u know any other platform is offering similar game, please lemme know.