The explosion stuns the enemy (stumble) which can get you out of sticky situations.
It has the explosive effect which deals 15 aoe explosive damage on each bullet which is also improved in AOE and damage by the demolition perk.
An alternative plasma weapon is the Sentinel’s Plasmacaster Downside to a sniper rifle is that it cannot be silenced. A high damage laser rifle that is best used as a sniper rifle or semi-automatic due to it’s perk of dealing 2x damage to full health targets. No real downsides to this gun aside from the fact that it should be modded with a non-automatic and sights.
Two-shot is one of the best legendary mods in the game. Overseer’s Guardian* – A late-game gun (combat rifle) can be bought at Vault 81 for a fair price (considering it’s power).