Yes, I shall comment, though in future I will not if a request is prefaced with "this game is a rip-off". If you have a question ask it.
The game is mathematically valid as regards the RTP for the side bet, based on the relative chance of attaining 100 spins without triggering a feature randomly.
The value of the feature subsequently triggered is extremely high, especially as there is roughly a 2 in 3 chance of triggering the feature with 3+ dice for free games, if triggered from Feature Guarantee (and therefore 2 multiplying dice, yielding from 3-18 games at x2-x12 through to 5-30 games at x2-x12).
This is a higher probability than the random trigger of the free games, which will most often be triggered on just 2 dice (so 2-12 games at x1-x6)
As with other events, the probability versus the average value derived versus the bet (in this case, the extra bet), yields the RTP.
Were the game to function simply as an accumulator and not reset on random triggers (ie: a game that would always trigger an additional feature after 100 spins, irrespective of any random triggers), on the extra bet listed, the RTP would far in excess of 100%.
To whit, the game has been designed in accordance with the game RTP and Feature Guarantee system, a mathematically valid system that is not a basic accumulator.
Woooof