5 year warranty. Peace of mind. Isolation of the console from the dimmers is desirable because device failure in one of the dimmers can place damaging voltages on the control cable. Without an isolator between the dimmers and the console, this voltage can cause extensive damage to the console's microprocessor circuits. With an isolator in place, damage, if any, is restricted to the isolator.
Electrical storms can also induce damaging voltages on control cables.
Barring a direct strike to the system, Doug Fleenor Design Isolators effectively protect against storm damage.