While I disagree with most of what the current POTUS does, I think this was the right move for a few reasons.

Under "normal circumstances" (which I will probably never see again in my lifetime) I might agree with your assessment.

However, none of us are privy to the actual intel of what is going on in Iran, and the intel that Trump has received is probably not as good quality as it used to be when more of the world perceived us as trustworthy, strong allies.

I can't begin to pretend that I understand all the dynamics of the Middle East, so for me it comes down to trusting the people in charge to at least try to "do the right thing". And there...I wish I had a lot more trust than I do.

Do I trust that Trump will take the available info, run it through the filters in his brain, get counsel from an assemblage of smart experts around him, and try to make the best decision for the world? Are you kidding me??

To my observation, Trump's brain filters out everything except "How can this make me more money?" and "How can this make me more famous?" (or infamous, I don't think he particularly cares which, as long as people are talking about him and he's dominating the airwaves.)

Reasons why this could benefit Trump were detailed well by Banksy here:

Banksy replies on Trump bombs Iran

Having us be at war or "under invasion" creates a lot of extra powers for him as President to bypass our customary checks and balances. I suspect that's what he's after ultimately, and doesn't care if he has to lie to get there.

And so...this Reality TV Show that our world has turned into continues to march on.