If you start using PA you won't have any feedback or trades done there and chances that people will accept your offer are really low. It is useful for a start on PA to show your PA offer on OSBot to get some easy trades going because you most likely are already trusted here.
If someone from here posted their offer on playerauctions and i saw someone more trusted on there for the same price, or someone as trusted that is cheaper, i would always go for them, not the person from here.
It would still create an opportunity for osbot users to create a safer way to sell/buy money if they could post there offers on here, even though people (including you) would chose another offer. There are also people who might accept that offer which gives more trust to that user on both OSBot and PA
this doesn't make sense, if people chose to use PA OSBot would in no way profit from this but neither would paypal or moneybookers. If people are allowed to share their links on OSBot it would just be easier for other OSBot users to access their offers.