If you say you drove a 3 minute lap but you didn't time it, that's an anecdote (and is what I mean). If you measured it, that would be a fact.
If you measure something and amount is N=1 it might be a fact but still a fact true for a single person.
I often don’t need a sample size of 1000 to consider something worth of my time but if it is sample N=1 by a random person on the internet I am going to doubt that.
If I see 1000 people claiming it makes them more productive I am going to check. If it is going to be done by 5 people who I follow and expect they know tech quite well I am going to check as well.
Every person I respect as a great programmer thinks agentic workflows are a joke, and almost every programmer I hold in low regard thinks they're the greatest things ever, so while I still check, I'm naturally quite skeptical.
So the “subjective” part counts against them. It’s better to make things objective. At least they should be reproducible examples.
When it comes to the “anecdotally” part, that doesn’t matter. Anecdotes are sufficient for demonstrating capabilities. If you can get a race car around a track in three minutes and it takes me four minutes, that’s a three minute race car.