This question doesn't deserve a serious answer, but I have a feeling that OP isn't the only one who's going to wonder about it so I'll give one anyway:
Assuming for a moment that there is a group like the NWO or illuminati pulling the strings behind world governments who want a single world currency, it would be fair to say that they would want one that they could retain some sort of control over, right?
I'm sure that they would want a currency they can print on demand and recall whenever they wanted, and of course they'd want to control the networks which it flows over so they can stop anyone's payments whenever they don't want payees to receive funds they don't approve of.
Ironically, I have just perfectly described the USD and SWIFT system to a "T."
Therefore, they already have exactly what they wan, and any changes to the current system would make a worse currency for them to control.
Meanwhile, bitcoin is completely uncontrollable. Nobody can stop anyone elses' payment once sent, not even the sender. This would not suit their purpose at all.
Bitcoin is also super-transparent. There'd be no way for them to hide all the money laundering and under-the-table business they do trillions of dollars a year in right now.
Most importantly however, bitcoin simply cannot be counterfeited. They would find bitcoin 100% unsuitable because they would detest the lack of ability to print more of it at will.
Try financing a multi-billion dollar invasion when you have to tax a population to do so; you won't get very far. Only a very corrupt system like the fiat dollar lets them do the evil things they want to do.
All of the code that makes up the bitcoin network is open source, meaning that you can look at it yourself, and assuming you can understand the coding language (C++ and python, mostly) you will know EXACTLY what bitcoin can and will do... And that's the code that all miners choose to run, in order to make them the most income.
This system is perfect for giving the common man an advantage that he's never had before against authority and governments; Bitcoin is truly 'the people's money' and not in any way capable of giving unfair advantage to a government or group like the illuminati.