Regarding the TED talk, he’s speaking into a microphone and getting echo’s from all the loudspeakers, same with his clicks. That would mess up his echo-location so yeah the cane makes sense.
Yes I figure the survival of the big bad world would play out as such in the wild.
Also clicking all day may be exhausting, could be the cane is a welcome interlude. 
Any echo locator dopes out there? We need real knowledge.
I remember a study where they showed that even sighted humans naturally use audio cues to navigate. They were blindfolded and asked to walk until they thought they were next to a barrier. And they were rather close.
I can’t remember if they used anything other than the sound of their own footsteps, but I specifically remember the study mentioning the differences in reverberation being the key–in other word, a form of echolocation.
Unfortunately, I can’t think clearly enough right now to think of what I should search for to find it. Maybe someone else can.