Multi-use of space at best. Probably instructions from the top.
Which competent planner of world class airports in the world would
relegate buses to calling at delivery basements? 
Perhaps the planners are not competent to begin with?
Only focus on the fine decorative details of the premise, yet
failing to solve the basic essential problems?
In other words, addressing only the wants, not the needs? Only
focus on profit gaining amenities eg. Rows of branded shops (mostly
for show), and turning a blind eye to the masses of airport
personnel, who has to experience living hell during commutes?