Unless you collect for the sake of collecting odd things, is there any conceivable reason to save impaired proofs or NIFC halves (other than silver coins)? I don't see a premium being paid for them...there are lots of listings on Ebay for them, but I didn't see any bids. I think they have just turned into spenders for me. Now, what to do with the sacks and sacks of pre-1981 Lincolns. Hmm...
If they are lightly circulated anywhere in AU you can roll them for your grandchildren as some of these grades may be desirable by then. But as for right now, they are only worth face value, or an album.