All windows will be one-way glass. People on the inside can look out, but people on the outside will just see a reflection of themselves when looking at the glass. This is intended for privacy. All windows will also be argon filled triple pane for temperature control. Low quality windows will not be able to keep the indoor temperature indoors. This will mean that the windows will still need to be of high quality.
Also, many apartments are on the second or higher floor. This will mean that a person can not look in from street level. However, someone across the street could look in, and this will be a reason for one way windows.