I'd be curious about the safety idea, given that most such pedestrian overpasses involve a couple of stories of stairs on either side. Their real purpose is to allow auto traffic full ownership of the intersection.

I've seen ones which have a spiral ramp, not stairs.

I wish they had more of those at busy pedestrian-auto intersections like busy train stations, etc., so that peds could cross at any time rather than having to wait for a light. A nice kitty-corner to kitty-corner X above an intersection. I think a compromise could be have these but not require ADA if the street level crosswalk is ADA compliant. Otherwise these get prohibitively expensive and don't get deployed at all.

At a train station where you're raising pedestrians to get over the tracks already it'd be less difficult to integrate.

Safer but because its trouble to use, not all pedestrians will take it.