Not sales hype at all- it cuts down immensely on the amount of wiring needed. You have 5 light in the back, five switches up front *and* in the back. Wires needed between front and back for traditional wiring- ten (two per circuit for three way switch operation). Wires needed for multiplex- two. Want to add switched somewhere else? Multiplex, run two wires to them, paralleled with other switches. Want to add a third with conventional- good luck!
In addition- the control wiring need not carry any significant current.