Paper Wall is a great piece of binary ice designed to force the Runner to dig for his Fracters. Designed along the same lines as Quandary, Paper Wall's greatest strength comes from how - if this is the only Barrier you're packing in your deck (and it should be, if you're playing this) - you have effectively just forced the Runner to spend time and money installing a breaker that is now completely and utterly redundant.
Now, you might say that Ice Wall is significantly better. After all, for just 1c more, you get a permanent Barrier that at least taxes the Runner a little whenever they run through the server. You would of course be absolutely right. If you're Weyland and you're looking to play binary ice, go ahead: play Ice Wall. But if you're short on influence and you're looking for something to fill a Barrier-shaped hole in your defences, Paper Wall can be a very good friend indeed.