Actually EMRG is the perfect CIWS to guard against those missile It is fast , efficient, plenty of munition whereas missile like HJ 10, or HHQ9 is limited in number and can be ovewhelm by opponent
Exactly. The test will focus on its limit, largest projectile, fastest speed, highest rate of fire etc. But it does not mean it can't be used in other situations. In fact, an EM gun (railgun, coil etc) can be used in different configurations from small slow to small fast to large slow. It is like a full programmable gun plus full programmable ammo in the same barrel.
The other main issue is people are fooled into believing the EM gun must be bulky. Since the power source and the barrel can now be separated, the power source can be shared among multiple barrels. And setting up additional barrels will be easier/lighter etc over time. This also means you can now focus on power source/charging tech because that would increase your navy's capability without building brand new ships and creating new barrels.