The raid reduced the oil production for a short period as the Germans were very good at recovering from bombing attacks so the question was “Was it worth the loss of men and material” on a short lived gain? Many asked that then but much higher costs were coming when raids deep into Germany begin. Also should be noted the Germans beefed up defenses around Ploesti due to the Russians staging very weak attacks that did little if any damage but spurred the Germans to ring the target with 100’s of AA guns, day and night fighter squadrons. One report stated you could walk between planes with so much lead being thrown up.
Same thing happened with the early war raid on Makin Island which caused the Japanese to fortify many Pacific islands, a blip for moral but cost many 1000’s down the road later on in the War. As a side bar during that raid by accident a number of Marines were cut off and left behind as they landed by Submarines...Didn’t end well for those guys.
If they hadn’t been tough to defeat, it wouldn’t have taken two world wars. :^)