I have a very good grasp of what provably fair is I've been betting since 2013 and played on the vast majority of the dice sites that exist
and I never called your site scam ,I said dice sites that offer deposit bonuses are strongly associated with scam (and it is my personal opinion ,not a generally known fact)
simply because  there were several dice sites that offered bonuses and all of them are offline , many gone rogue
example:duckdice got lot of flak for it and the owner is wearing red tag still and stopped offering bonuses , you can search the forum yourself for the full story if you want to
oh and 2% house edge is what makes all the difference , with 1% house edge and 50x wagering requirement it is too easy for a good dicer to achieve the rollover and withdraw