Prevent accidental falls off the platform onto the lower track area, suicide attempts and homicides by pushing

Prevent or reduce wind felt by the passengers caused by the piston effect which could in some circumstances make people fall over

Reduce the risk of accidents, especially from service trains passing through the station at high speeds.

Improve climate control within the station (heating,ventilation, and air conditioning are more effective when the station is physically isolated from the tunnel).

Improve security — access to the tracks and tunnels is restricted.

Lower costs — eliminate the need for motormen or conductors when used in conjunction with Automatic Train Operation, thereby reducing manpower costs.

Prevent litter build up on the track, which can be a fire risk.

Improve the sound quality of platform announcements, as background noise from the tunnels and trains that are entering or exiting is reduced.