"All welcome package bonuses are subject to a minimum 50x play-through requirement before being transferred to the player’s cash balance."
Basically, this means that you need to roll-over the bonus deposit funds 50 times in order for whatever is left to hit your account.
With an unknown house edge, that almost certainly means you'll lose both your initial deposit and your bonus deposit within a few tries, even playing a low house edge game.
That's how deposit bonus works on all casinos, deposit bonus or welcome bonus or maybe reload bonus is not created to give players better chance to win something. I can even say, deposit bonus gives players more -EV due to its wagering requirement and other requirement. Indeed when players take deposit bonus then they will get more balance but in fact the balance is locked till players meet the wagering requirement. Anyway 50x rollover is higher than other casinos, afaik most other casinos gives lower rollover for their deposit bonus range from 30-40x.