I took a tour in 2007, given by a guide who was a German soldier in the area in 1944, of the area where he was killed. At the end of the tour we stood on the hill that the US Rangers suffered so much for. This hill is very nearly in the suburbs of Duren, the industrial town that was the focus of much of this effort. You can readily see what the Americans thought they saw in 1944, if we can get through these few miles of forest, we can decisively deploy our mobility on the plains up to the Rhine. The Americans were resigned to slugging it out somewhere to get to a friendlier terrain.
Having said all of that, my guide thought the same as you, why fight here?? I think the answer was, it was where the Americans were with enough strength to matter and to be able to coordinate with the British. South of here is the Ardennes and that was worse than Hurtgen from a terrain standpoint (and a source for German replacements from November 1 on due to the Germain buildup there). South of that were the 3rd and 7th Army that had plenty of their own issues with terrain and could not count on the British for coordination.
Hurtgen is an ugly place to fight (so it is a rather beautiful place to live). And maybe if the Americans and British had shifted a bit to the left they could have found some German gaps. But many of the main rives in northern Europe empty into the sea in this area, so you run into the issues that doomed Market-Garden.
In October 1944 the Germans still had enough resources and short enough lines to put up a stiff fight where ever the western allies decided to pick a fight. And the West Wall was just stout enough to add to Allied misery.
I think October 1944, given the fatigue of the Allied forces, supply situation and the short lines left to the Germans to defend, was going to be a bitter time for the Allies on the Western Front.