The Advantage of that light weight is it's faster on the call. the Us Recently evaluated the C27J for potential use as a Gunship light. Almost introduced it. A number of other Western nations are now moving to pick it up including Italy in the form of the MC-27J Pretorian and the AC235 form Jordan,
The key advantage being that the lighter platform could take off from a wider number of fields. be built in larger numbers for a lower price A light gunship can also be used for more patrol and recon missions. It would also not be the first time a craft of the Y12's weight class the Britten-Norman Defender for example.
The lighter rougher plane makes sense if it is going to be forward deployed, which works well for expeditionary forces but that is not China's circumstance. A smaller plane is always going to have less range/endurance, damage resistance, and payload compared to a larger plane. It would be more cost and mission effective for China to have fewer air bases further away from potential ground attack and larger planes which can both deal and survive more damage and engage the enemy for longer periods further away from friendly targets.