I use High Scatter Amplifier somewhat frequently on smaller high-tech ships. All of which involve Graviton Beam and sometimes Tactical Laser and LR PD. When Pulse Laser is still not efficient enough for anti-shield, HSA Graviton Beam is the only alternative for shield-cracking. Rarely, I use it on bigger ships when I recover them and need to make do with whatever weapons I have in cargo until I return home and outfit them properly.
I view High Scatter Amplifier as alt. Graviton Beam mode. I use Graviton Beam more with HSA than without it.
What is it good on?
Assuming no Safety Overrides on NPC ships...
Wolf: One Graviton beam, one tac laser, and two LR PDs. Maybe better without it and just beam the target from long range, but HSA beams kill faster. It is the only way Wolf could brawl head-to-head and trade shots with SIM Lasher and win, especially now that Lasher has 0.6 efficiency double LACs.
Tempest: Two HSA Graviton Beams and your choice of small missile (I picked Breach, linked with main guns) with Missile Autoloader.
Brawler (TT): Two Gravitons and missiles like Tempest above.
Glimmer: Graviton Beam, two Tactical Lasers, two LR PDs (with ePD). Not as safe as without HSA but will kill faster than without. More range than IR PLs.