I certainly agree that a rifle isn't my preferred choice for clearing a POI. The OP's math on the matter rings true. A silenced rifle might be nice for stealth, but I'd rather just clear a POI using arrows and save bullets/slugs for hordes.
A rifle is more useful for horde night, but still not my main choice, though I suppose that's going to depend on the base design or if the player is being mobile. Having bow-kited hordes, I could maybe see doing it with a rifle, but if your goal is earning lots of experience points then you're going to be in a horde base.
I used to use a rifle for hunting, but hunting with stealth and bow has been awesome in A21 and V1.0.
I have used a tricked-out sniper rifle in the wasteland, spending the night just one-shotting distant Z's from a height.