Ann: Unmarketable Parcel Share Sale Facility, page-3

Neither. It just means that the company is giving shareholders who have only a few shares, the opportunity to sell their shares without having to go through the ASX and ay transaction fees.
Advantage for shareholders: Usually this means that the the shareholders do not have to pay a big chunk of the value of the shares in transaction costs.
Advantage for the company: It gets all those pesky tiny holdings (and annoying shareholders) off its books

Advantage for a 3rd party: If a 3rd party is prepared to bear the time and expense of soaking up all these tiny holdings, it can gain a reasonable sized holding without affecting the share price, because the holders who sell their "unmarketable parcels" have been waiting for just this type of opportunity, so they can sell outside of the ASX.