So in other words: if they have a good CV, they'll get through to the next stage regardless, but if they're a punt candidate then the cover letter might make a

So in other words: if they have a good CV, they'll get through to the next stage regardless, but if they're a punt candidate then the cover letter might make a difference, maybe? I would then ask: if I'm a punt candidate to begin with, the number of interviews I get is primarily a factor of how many applications I fire off into the crapshoot, right? What's the increase in success rate for applications with cover letters? Is it enough to outweigh the reduction in applications I can send from hand-crafting each of them?