I agree. The "fishless" algae is often heavy and hard to get off the leaves. On the other hand, there is the possibility at least that plants carry a tiny bit of live "inoculant" (a bit of the good bacteria we want) to perhaps give a bit faster introduction than the normal tiny random bit an empty tank gets. Plants are also give some entertainment of sorts during fishless cycling and provide practice time prior to fish when you can think about what parameters you are going to adjust for the plants. Also, the fishless cycling environment won't hurt them - the warmer temp is ok and as long as the tank is not heavily planted, they won't process very much of the ammonia.
~~waterdrop~~