I have never brought binoculars to WDW. But here are the times when I thought that they might be useful (actually, I was thinking more in terms of a telephoto lens, but not necessarily for taking pictures - just for seeing detail):
At AK for farther-away animals and theming details (I've never visited AKL, but I imagine they would be ENOURMOUSLY useful for savanah viewing).
At MK to see detail on the castle towers (espcially during the HCOE overlay) and to see Tink exit her window on the zip line.
From the MK resorts to see the park details better.
I probably wouldn't bring them because of the weight factor, unless I was driving. But that's just me.