I found they did not because they died before getting a second salvo off.
They are artillery units, when AI ships can close the range on them they just die (which I agree with for gameplay/balance reasons.)
Their intended targets all have Anti Matter immunity (or radar dampening) so they are hardly useful.
And so many of the AI ships are under forcefields anyway, as those are Anti-Matter immune, the bombards can't even attack them while the forcefield is still intact making them even less useful.
Did their powerful alpha-strike kill a lot of AI units? Yes.
They did not get a second shot off however and their construction costs were not worth that single salvo. (To me anyway).
Having said that, I can see where in mid-game these things are too powerful. Unless there is a force field in system, they can clear an AI system in 3 to 4 salvos, it's not until the core/homeworlds that their usefulness goes away.
(I will admit to only playing a single game recently with bombards, maybe my experience was an outlier?)
edit: To clarify, after clearing the warp point with short-range ships (fighters/bombers/etc.) and warping my Bombards in, they got roughly 1 kill to every 10 or 15 my fleet ball got. And that was often clean up after my fleet ball had closed the range and knocked the force field/guard post down to allow the bombards to even attack.
I had wanted to use my bombards as my primary attack to take advantage of their range and use my fleet ball to protect it from mobile AI ships but sitting there taking fire from a Missile guard post and the wormhole guard posts without returning any fire forced me to use my fleet ball as my attack and the bombards for clean up.