Iran's retaliatory attack on Israel was obviously designed to do little more than save face for its leadership. The slow-moving barrage was telegraphed and structured to inflict little or no damage. I guarantee that Iran's government knew most of their drones and missiles would be easily dispatched by Israel's US/UK-augmented air defenses.
The same can be said about military commanders in Israel, the US and the UK. They know that Iran’s attack was designed to fail.
You can't give two hours for a modern air defense system to anticipate slow-moving drones and expect military success. In this case, AP reported a 99% interception rate, which translates into a complete and total military failure. 
But you can use the fact that you "responded" as propaganda for domestic consumption, as well using the slow-moving attack as a message to Israel that they are within the reach of your military capabilities should Israel decide to escalate once again … like Israel did when it attacked Iran’s embassy in Syria without telegraphing their attack because Military Tactics 101 is using the "element of surprise," which the Iranians notably did not use in their retaliation. Nor did they activate Hezbollah, by the way, which they would've done had they wanted to overwhelm Israeli defenses to actually inflict some real damage. 
But they didn't.
For me, that's the big takeaway here ... that Iran’s response comes with a major "out" for everyone involved. Israel doesn't have to respond. They could look at the bottom line and take the "win" from illegally killing two generals by bombing an embassy located in a sovereign nation without having to absorb any real price for doing so. 
Instead, they can just move on with their brutally-calculated plan to make Gaza unlivable. 
Then again, that's the rub here. I believe that Netanyahu purposefully attacked Iran's embassy because he wanted to draw Iran into conflict and, in so doing, re-focus the world's attention away from the starvation and killing of Gaza’s civilians. Interestingly enough, the murder of World Central Kitchen’s aid workers and the attack on the Iranian embassy both happened on April 1st. A cynic might anticipate Netanyahu’s desperation to now shift the narrative away from WCK by further escalating his engagement with Iran. Given the PR and geopolitical disasters Israel created on the same day, I doubt that Netanyahu is looking for a way out of responding to Iran’s response. He’s going to cling to Iran like it’s a life preserver in a turbulent sea. Even more, I believe he’s also desperate to shift the domestic narrative away from ensuing revelations from Israeli news sources about both the Lavender A.I. targeting system and Ha'aretz's devastating story on the "kill zone" rules of engagement the IDF is using inside the Gaza Strip.
Israel is mired in a PR quagmire and Netanyahu is mired in an ongoing political disaster. Bibi needs his long-sought war on Iran to cement his war-dependent political survival, which has come under even more scrutiny inside Israel over the last week. And after WCK, Bibi also needs to distract the Biden Administration and divert the eyes of the US media and the American public away from the brutal truth of what he is doing to the people of Gaza with US-provided weapons. 
As a matter of propaganda, it is ironic that both Iran and Israel could walk away from this with domestic PR wins. It wouldn’t be the first time that the fates of Bibi and “the Mullahs” were intertwined. Iran’s leadership is signaling that they’ve got the PR win they wanted. They’ve "deemed the matter concluded." 
Sadly, I don’t think it will be enough for Netanyahu.
His political desperation and ethno-religious bloodthirstiness have a synergy that time and again trumps rational geopolitical thinking and the best interests of its primary benefactor. War is his political lifeblood. Thankfully, the Biden Administration has, as reported by Axios, told Netanyahu that Iran’s attack is not grounds for US involvement in an Israeli counterattack. Biden’s NatSec team sees the off-ramp here … and, thus far, they are willing (and probably relieved) to take it. Unfortunately for them, though, the political ties Israel has cultivated with Evangelicals and Republicans are a de facto political trump card Netanyahu knows he can play over and over again. And he’s an unrepentant gambler.



It was an elaborate, orchestrated, choreographed tit- for-tat attack. Think of the cost, from the manufacture of all the missiles, anti-missiles, and drones involved, to the time, energy, and resources involved, to the training of the troops to use them, to the carrying out of the attack and countering it! It reminds me of this stupid handshake ritual between India and Pakistan!
https://youtu.be/VtGj8sM2Y50
Humanity has everything it needs to make the baby step from violent talking apes to civilized cooperative humans, and the benefits would be IMMEDIATE; war is a constant hassle and drain of productivity. Who WOULDN'T want to be cured of cancer and have a better, healthier day, starting today? But for some reason we refuse to let go of the insane ritual of war.
I wonder if it's just me, or if John Lennon's mantra, "Give peace a chance", is starting to seep into the everyday consciousness of humans worldwide. We, as a species, have NEVER once given peace a chance. Humans have worked together globally on many things (eliminating polio, decreasing ozone emissions in the 1970s and 80s, fighting AIDS, etc.) but NEVER on decomissioning armies and weapons.
https://youtu.be/C3_0GqPvr4U