This new conventional warhead is almost as powerful as the nuke, but it has very low barrier for using in the battlefield, unlike the nuke.
Conventional Weapons rely on breaking of chemical bonds.
Nuclear weapons go one whole level deeper, and work at the nuclear level, breaking up of nucleus.
The scale is just all together different. No conventional weapon can match the capability of nukes, with anything close to its size.
As pointed by
@Nilgiri , the most powerful conventional bombs, weighing many kilotons, have an explosive power equivalent to only the smallest tactical nuclear weapons, weighing some kilograms.
Also, the DF ZF, is no where near to a nuclear weapon, because it would either be a kinetic weapon, or a dual, kinetic + explosive weapon, and none of this can come anywhere near to a decent size tactical nuclear weapon, in the respect of net energy delivered against the target.