Disruption ?
It's quite often closed when attacks take place, suggesting the russians know it could be taken out, if and when Ukraine wants to.
I'm not sure how much the bridge is used for logistic re-supply, ships can bring in a lot more than a train (or trucks) over a bridge, which is why they targetted the ship the other day.
You keep saying they tried to "destroy" it, none of us actually know that, damaging it using less important ordanance is cheap(er) compared to using weapons like storm shadow, which the russians don't seem to have any defence for, and they so far, seem to have been used quite sparingly (and effectively) on proper military targets such as ships, hq's, and even a submarine.