Usually plant decoratives in Minecraft do not drop their respective item normally, especially if its abundant and/or cosmetic like grass and ferns. Although you could certainly add some sort of semi-rare "Seed like" drop for the leaf piles, having stacks of leaves fill up my inventory is a real pain. They should be treated like other cosmetic plants, you can only obtain them with shears.

yes its intended on both, it can be used decoratively

does that means that leaf carpets not being affected by gravity is also intended? I was going to report it here right now, but I think that this is something to report on Quark's github

Intended, to work like how Quark's work.