In a nutshell, I oppose the building of this structure as the cost in terms of federal money, displaced homes and businesses, and the destruction of part of a neighborhood, did not justify the net gain of the project, amounting to only about 30 seconds of commute time on those lines.
Here is a 2011 article written by Ed Zotti from the Chicago's free weekly, the Reader, that describes a complete overhaul of the Red, Brown and Purple Lines. In a scheme that Zotti and his colleagues exhaustively created, the three lines are reconfigured to more adequately serve the needs of riders on both the north and the south sides of town.
As a patchwork, temporary fix that the CTA currently proposes, the overpass makes little sense. However when integrated into a visionary plan for the future as it is presented in Zotti's article, it may be something worth considering.
Buyer beware however, the overhaul comes at a cost measured in the billions, not the millions.
Money worth spent in my opinion but I may be in the minority on this one.