This is the W Hotel Union Square, located on the northeast corner of the park. The building itself has been there for decades before the W Hotel chain took over and converted it into a boutique hotel. The external façade were kept the same while the inside were gutted and turned hotel rooms.
Notice the flight of fire escape stairs on the right of the building. Imagine trying to climb down or worst, climb up those stairs. So are you a stair climber or an elevator rider?