I used a 4 port passive hub as a way to accept a pixelnet signal from the active hub (no power via the cat5) to a distant location ... Where I would then inject 12v power from a $8 ray waterproof power supply and then run some SS nodes from there (but limited by the power injected locally).
The passive hubs take pixelnet in ( not Dmx ) and allow you to inject power (or run a dedicated spt2 power cord) as opposed to having power injected over long distances on a cat5. I think over 100' runs may be candidates for passive hubs, because cat5 isn't really rated to carry power long distances.
It also gives options for potentially reducing the load on the active power supply.
So if you were doing a rgb roofline, you might use passive hubs to distribute the power more easily, potentially. Just an example.
There are some misleading comments in this thread. Don't bother using lor if your going to run smart strings, use Xlights, lisp or vixen.
If you want to sequence with lor, fine, just replace the lor scheduler / show player ... with Xlights and your in business.