@The_Good_Captain
I would agree with you if the smoke were placed indiscriminately all over the beaches, but I was suggesting specifically firing smoke directly in front of the defending gun emplacements, to blind them while the landing craft were approaching and the troops were disembarking. The smoke would dissipate after the allies stopped firing it, and then the gun emplacements could come under direct fire again. BTW, the allies did utilize direct fire at the gun emplacements on the beaches but those guns were still able to inflict terrible casualties before the Higgens boats even reached the shore. So, the efficacy of the fire support shouldn’t be a particularly big impediment to screening the approaches and landings from the enemy guns. If the allied direct fire support were so good, the gun emplacements would have been knocked out before the landing craft were even launched. It wasn’t and they weren’t and a lot of soldiers died because they slowly (12 knots) advanced across a long distance (6,000 yards/3.4 miles).
From the National WW2 Museum web page: “But at nearby Omaha beach, the US force suffered serious losses. The naval barrage and bombing raids on the German defenses were ineffective and the Americans encountered a crack division of German troops.”
From the Warfare History Network web page: "At 6:30 am the landing craft carrying Company A quickly closed the distance to the beach. When it was about 30 yards offshore, the flat-bottomed vessel struck a sandbar. As the ramps were lowered, the troops were fully exposed to the fury of the German machine guns. Many of the first men who exited the landing craft were slain by machine guns positioned to have interlocking fields of fire. Their lifeless bodies toppled into the water. Some men chose in their desperation to jump overboard instead of exiting the front of the craft. Once in the water where they were weighed down with their equipment, they faced a life-and-death struggle to keep their heads above water. They thrashed about while strapped to heavy loads. Those who could not get free of the loads drowned.
Struggling forward through a hail of machine-gun and shellfire, the survivors desperately sought cover behind tank obstacles placed by the Germans. Enemy positions were well concealed, and the hapless riflemen of Company A, unable to effectively fight back, fell in mangled heaps. Terrified and demoralized, the green troops of Company A had entered the worst killing zone on Omaha Beach. “They’re leaving us here to die like rats!” screamed Private Henry Witt above the steady roar of enemy fire."
Putting smoke directly in front of the German defenses during the approach and landing seems to me to be a better tactic.