The attack on Metz was an unnecessary spilling of American blood, wasting men’s lives in a vainglorious show, where, at the end, all that was needed was a 175mm cannon.
Metz was a key location that had to be taken. The extensive forts there, the rivers and rain, and Ike giving Monty priority on gasoline, inhibited flanking attacks and left frontal assaults as the only course of action. It had been hoped that the forts would not have been heavily manned, but the Germans poured in reinforcements into that sector because they saw Patton as the primary threat, not Monty to the north. Read the chapters on this by Dennis Showalter in his book “Patton And Rommel: Men of War in the Twentieth Century”
“more good guys die in offense than defense” usually true but it also depends upon how you do your offense. WWI trench type, over the top and into machineguns, or do flanking attack as in Manstein’s French Invasion, or the Bradley/Patton breakout of Normandy.