It seems, from what I've seen, to be a "feature" found only on mechanical dial machines. I guess it was a way manufacturers could add one more bullet point to the feature list for BOL machines even though it was just the point on the dial for the heated dry cycle. It's rarely, if ever, found on electronic control machines, at least not that I've ever seen. Our GE Nautilus had the "Plate Warmer" point on the dial, just that ~30 minute dry phase if you had the Heated Dry option on, but the one or two times I ever tried it as a plate warming method, it wasn't very effective. By the time the interior of the tub got maybe 100 degrees, it was already time for the dial to reach "Off". Perhaps if it was used on a machine with forced air drying it could prove effective, but I just don't see the need when placing the dinnerware in a still-warm oven for a minute or two after baking is done is just as effective and is using no extra energy.