The purpose of the attack on Israel is not to invade Israel or win. There was no military objective except it was retaliation for settler violence. On the other hand, there was definitely a political objective to bring the world's focus back to the conflict, to disrupt the Israel-Saudi deal, to take hostages and get Palestinian prisoners released from prison and most importantly to disrupt the status quo and create a need for a 2 state solution (although in my opinion it will not happen).
A number of factors led to Hamas’s operation in southern Israel.
www.aljazeera.com
Of course the Israelis do. They sit on the hills of Sderot and watch Gaza being bombed, while sipping tea and cheering and chanting "Baruch Hashem" or some shit like that.
That is what I said. Many of the explosions you see are the Trophy APS and the video Klatuu posted did have a damaged tank being towed away. Am sure that tank didn't blow up by itself. So yes, Hamas is unlikely to inflict significant damage on the Merkavas with their RPGs but the probability of damage isn't zero.