Yes. For meads, you want to get the mead off of the gross lees (the thick sediment that forms in the bottom of the vessel), and to reduce headspace when you siphon to a new vessel. During primary, you can have alot of headspace due to foaming and all of the c02 produced (plus it's easier to stir it!) but once fermentation slows and stops you want to minimize any headspace to avoid risks of oxidation.
Also, sitting for a long period on the gross lees can impact the flavor after about 45-60 days.