Yes, they can cause maybe hundreds or more civilian casulties, bombard important sites, disrupt the IDF preparations and bases. But at the of the day Israel will survive and recover. The big dilema is for Hezbo: You dont use these weapons, you are ineffective. You use these weapons and cause heavy damage that no democratic country will tolerate, and poof...Hezbanon will turn into the worlds biggest sandbox. So if you think about it, they are the ones with the problem.
Abbas to urge UN to pressure Israel to permit entrance to Palestinian refugees from Syria (Haaretz)
from the article: MESS Report / Can Israel fend off a Hezbollah armed with Syrian rockets?