Paypal would do very well buying and selling Bitcoins. Buying bitcoins with Paypal is a very common request, which most sellers won't do because Paypal makes it very easy to rip off the seller.
Where are you observing that it's a common request? Could it be a common request because it's easy to rip off the seller, in the same way that assistance transferring a dead relative's funds out of Nigeria is a common request?