Because it is.
Iran gets massively fucked over and embarrassed, after taking advice from allies and their own hubris that Trump will do nothing because of his legacy, his base being against wars, and people thinking he is all talk.
Their Nuclear strategy now must start at step 1, (or earlier depending on how important those lead people are and their file/note keeping is).
After such an embarrassment they needed a way to say that they are getting a "win" without inviting more retailiation on by majority of the world.
So they'll launch a strike that they prementively warn will happen so they can physically strike back and they threaten the closure of oil passage in the sea, (which they'll never be allowed to do by their China masters) so that when they eventually come to the nogiating table they can project strength through this toothless threat.
Finally for Trump if all goes well this is what he has to gain:
- Tell the world that he is truly not afraid of military action.
- Project strength to backup his threats.
- Encourages enemies, (Russia / China /Mexico / EU) to negioate and come to the table. (if you wonder why EU and Mexico, keep in mind economic attacks can now be backed up that Trump can and will take action that may go against his base/popular support in order to back up his threats).
- Stops Iran from getting a Nuke.
- Hopefully stops Isreal's drive to pull America into the region and he can tell Bibi to fuck-off for the rest of his term. (which if we remember he was in the process of doing before these attacks).
- People forget that this happened or at least forget the fear they had during this time, like they did during his first term.
