It depends a lot on how you use it, and how much effort you put into getting a knack for using it (which is rough because you're always worried that knack might be out of date within a month or two).

I use Claude, Codex, and the Gemini CLI (all "supervised command line agents"). I write Go. I am certain that agents improve my productivity in a couple common scenarios:

1. Unsticking myself from stalling at the start of some big "lift" (like starting a new project, adding a major feature that will pull in some new dependency). The LLM can get things very wrong (this happens to me maybe 20% of the time), but that doesn't matter, because for me the motion of taking something wrong and making it "righter" is much less effort than getting past a blank page, assembling all the resources I need to know how to hello-world a new dependency, that kind of thing. Along with "wrestling for weeks with timing-dependent bugs", this kind of inertia is one of like two principal components of "effort" in programming for me, so clearing it is a very big deal. I'm left at a point where I'm actually jazzed about taking the wheel and delivering the functionality myself.

2. Large mechanical changes (like moving an interface from one component to another, or major non-architectural refactors, or instrumentation). Things where there's one meta-solution and it's going to be repeated many times across a codebase. Easy to review, a lot of typing, no more kidding myself for 20 minutes that I can make just the right Emacs macro to pull it off.

3. Bug hunting. To be clear: I am talking here about code I wrote, not the LLM. I run it, it does something stupid. My first instinct now is to drop into Claude or Gemini, paste the logs and an @-reference to a .go file as a starting point, and just say "wtf". My hit rate on it spotting things is very good. If the hit rate was even "meh borderline" that would be a huge win for the amount of effort it takes, but it isn't, it's much better.

I'm guessing a lot of people do not have these 3 experiences with LLM agents. I'm sorry! But I do think that if you stipulate that I'm not just making this up, it's hard to go from here to "I'm kidding myself about the value this is providing". Note that these are three cases that look nothing at all like vibe-coding.