Gregtech disallows any cobble-derived product except gravel, which takes very large amounts of time and energy to create. this is because no-one was using the recycler without a cobblegen, and it just became a mandatory extension of any recycler setup. Then no-one would actually use the recycler to recycle unused items. it makes you give a fair amount of consideration as to how you are going to fed it, and gives the alternative matter fab amps a use. my personal favorite is to use all that excess beeswax.