I think you are confusing APS systems in general (of which Shtora is one) and the subset of APS systems that are hard-kill such as Trophy.
Of course regardless of efficiency, an APS system has to be installed in the first place and it is possible that that is not the common case in Ukraine.
APS generally refers to hard-kill systems like Trophy/Arena. Things that actively go kill the missile or projectile coming towards the fighting vehicle. Shtora is not active, it simply disrupts the laser guidance (if it can detect the beam in time). It's no different than an ECM jammer on a fighter or surface ship.
Of course regardless of efficiency, an APS system has to be installed in the first place and it is possible that that is not the common case in Ukraine.