Basically...
Moneybookers requires a huge amount of verification before you can send any money. This can take several days, and many people are simply unable to fulfill the required steps in order to use the system. Once verified, however, it becomes extremely simple to use so long as your financial information remains static.
To say Moneybookers is "safer to use" than Paypal is incorrect. For a buyer, Paypal is definitely much safer than Moneybookers, because you are protected. Moneybookers, on the other hand, provides no security for the buyer, and instead nearly 100% security for the seller. So, if you're RECEIVING a payment, Moneybookers is extremely safe. But if you send money, you have no way to recover it if the other party does not follow through on their end of the deal.
In summary:
Moneybookers = safer for the receiver
Paypal = safer for the sender