This situation was for Iran to save face. They had to appear to "retaliate" for the bombing that killed some of their generals. They, and the powers that be, knew that none of those drones would make it through the Israeli missile defense systems, but they had to have a show of something.
Places like Iran know that they have nothing to offer, in any real military attack. They have to resort to terrorist, guerilla warfare through proxies. There is no such thing as a WW3 with Iran.
They would have to align with the rest of the middle east, China, Russia etc...for it to become another World War. None of these countries can do anything on their own.
Those cheap drones can do a lot of damage in a drawn out war.
Iran doesn't need to "Win" a war to win a war.
As other's have said expect terrorist attacks to start occurring over the next 9 months. You can bet your ass Putin and Iran, are doing everything they can to make something happen in Europe/America.
You can't really attack Iran because it's nested between Iraq and Afghanistan. Any attack on Iran would be futile.
It's important to note that China-Russia-Iran is one hell of an axis of evil.