Okay.. hmmm.. how to put this..
Let me just say the FISM is an organization that would like to rule the entire world of magic (feel free to translate that to the most extreme form of ownership).
As for the contest in particular, first off you are completely depending on a FISM Member Society (magic club) and/or its president in order to join the competition, and you will still have to pay quite a lot of money for the registration of this relatively exclusive contest (150 contestants in total). On top of that, in order to win you are completely depending on the jury, who is generally made up out of the all-knowing kind of magician and for that is impossible to judge everything in a fair manner (which is why Lennart Green was disqualified in 1988 for very wrong reasons and the jury didn't reconsider their decision. Mr Green got back in 1991 with the same act and won the competition). And although every now and then there are notable winners, calling the winners "the world champion of magic" or even "the best magicians in the world" is completely unjustified for those reasons.
That's basically the short version.