I bet one getting poked has more to do with it than you think. We have two lungs too after all and they're a lot less exposed than your eyes. I use that redundancy with a disturbing amount of regularity when biking too... with something getting in one eye and temporarily disabling it (I really need to look into some form of eye protection from road dust).

But thinking of depth in vision like color also makes a lot of sense, it's extra information but not an extra "physical" dimension. You can't see inside a sphere but you can a circle.

I can think of even more ways we benefit from having two eyes, like not having to whip your head back and forth if you want to scan the landscape.

But if they were mainly for redundancy the eyes might be closer together, like the nostrils (and unlike ears, which help with spatial awareness).

I think the fact that modern life requires less and less depth perception (when’s the last time you had to judge how far to throw a spear, etc) might be leading us astray here.