So that people could... 

Have easier access to token booth and clerk. It would make the station safer and more user-friendly. There used to be a walkway that ran the length of the block. Great in bad weather. When budget cuts years ago forced the loss of the token booth at that end of station, at least having a walkway afforded some egress of there was a problem. Now there is neither a token booth, nor walkable ("runnable") access to the clerk. The area is very confining in case of crime. To make matters worse, when they constructed the new offices for MTA staff at that end of the station, they didn't even make windows in the walls to suggest to prospective muggers that they would be seen. Nice work. All that money and inconvenience to the commuters and no one thought about a mirrored wall like the ones in every MTA police station?