The line voltage is positioned with one of the access plates. The low voltage wires are positioned to the other access plate to ease daisy chain installation.
Also line voltage and low voltage wires are typically ran in separate conduit (in accordance with many local codes). This wiring access separation on this fixture allows the fixture to be in compliance with these codes.
An RFD would need to be entered for the line voltage and low voltage to be ran to the same access plate.