Mostly they don't publish weights, because at the end of the day it just doesn't matter.
So if bindings made of bricks and snowboards made of cement rode better, you would be all over that shit! We could totally get some iron bindings that are just as stiff as some carbon fiber ones... and cheaper too! If it doesn't matter... why is that not the trend?
Cars are getting lighter, bikes are getting lighter, so are snowboards, bindings and boots. You can find a weight for the first two... why not the snowboard stuff?