It was a modern alternative to standard wiring/switching which was to revolutionize the electrical industry using space-age technology. In other words, someone tried to create a better mousetrap but in the end, the tried and true method won out.
Imagine not being able to replace a switch with a dimmer?
Also - the "system" was sold with other benefits and features, such as "master control panels" where every switch relay could be wired to one or more "master stations" where you could control 16-24 lights and see what is on and what is off at a glance, as well as be able to push buttons which controlled assigned "groups" of switches, or perfom assigned tasks (1-on, 2-3-4 off, 5 on, 6 unchanged, 7-8-9 on, 10-11 off) @ 7am... and vice versa at 10pm...