BREAKING: Israel eliminates 4 senior Iranian intelligence officials
Consider the impact of killing 4 senior intelligence officials. You will need to promote people beneath them to take their place, and then promote others to take the place of those just promoted, etc. This could cause 16 or even 20 people to get promoted. It is possible that some of these people are Mossad assets. It could also be that some of those promoted are incompetent. Either way it causes chaos within the organization at a time when it is the most damaging.
Also, those who are getting promoted can see this as a death sentence. If the leader of the intelligence agency can't protect himself does anyone really think he can protect anyone else. So it shakes the confidence and undermines trust in the organization. It is a lot easier to get people to flip if they have no trust or confidence in the existing regime.
Meanwhile Iran's attacks are on residential sections. The people killed probably do not weaken the IDF but it does cause people to hate and despise Iran even more that they would target civilians.