Sniper works with Critical Hits which ignore negative offensive reductions so for example, having a Scope Lens and Focus Energy is effectively x2.5 Damage, and Merciless can be combined Poison to secure Critical Hits for 1.5x Damage.Another question here, are there any abilities that prevent the loss of stat boosts?
EDIT: If there isn't an ability, are there any other strats that can have this effect and still be viable?
Critical hits also bypass opposing Defensive boosts. So if you switch into a Poison Heal Kyogre-Primal and Critical hit it bc you have Merciless, as its already Poisoned, your Fleur Cannons, Psycho Boosts, Draco Meteors, etc. will always deal 1.5x Damage, which is nice, while also bypassing their Quiver Dance boosts.
It ignores your -Atk, -SpA and ignores their +Def and +SpD due to the way Critical Hits work.