What is the expected effect of hammering them one day and asking for peace negotiations the next? Start a war you've made an enemy.

This was a sop to Netanyahu, but only because it worked as a grift to enrich the oil companies, Putin, the folks trading on "predictions", and Trump himself. Trump will play with this yo-yo as long as he can because, to date, it's likely been his most lucrative piece of graft, and a gift that keeps giving. As long as the body count stays low, he can continue with this farce, at least until the Republicans in Congress grow a set of balls and decides to rein him in long after so much theft, death, and damage has been done.

The worse all his options will be and thr more expensive his do nothing approach gets.

He is choosing by far the worse option.

He only has bad options and they all extend the financial pain for Americans while keeping the military tied up in the middle east. Doing what he's doing now is the worst option for the US.