I think that, if you have already established your company and brand as Aurum Casino, then you may have to really debate about using it. If people are going to know you as Aurum Casino then you may want to spend the money because you don't want someone else to have the domain down the road, if people are going to think to themselves, "I really like Aurum Casino, I wonder how to find them online. I'll just try, aurumcasino.com and see if it works." Many people will do this. If they type that in and someone else comes up, they may just stick with them. If that other website looks good and they like it, they may never give you a second thought.
However, if you haven't fully established your company and branding as Aurum Casino, I definitely suggest finding something a little different so you don't have to spend so much on a domain name. As others have said, it's money that can be spent in other more useful places.