The problem is that the Iron Dome system cannot hit or shoot at a Qassam rocket or mortar in flight. It is not designed to do that. And It also costs 1000 to 10000 NIS for each attempt, bankrupting you. It does missiles, not rockets and mortars. For Rockets and mortars, you need the Raytheon system.
Judge orders Jerusalem Gay Pride attacker to undergo psychiatric evaluation (Haaretz)
from the article: Defense official: Egypt border fence funds could have paid for Iron Dome