Tried the Denoiser for the first time tonight. A couple of times, so this isn't the first render I used it on, but I do like it a lot.
It obviously "removes" the grain, but the reason I like it is that it tends to give the render a different look.
I haven't tested this image without the Denoiser, but the iterations speak for itself, stopping the render at 52 iterations, probably a minute & 30 at most. Mostly because it already had enough detail to stand on its own but I also liked the smudge "effect" it gives, as I said. It brings a cooler aesthetic in my opinion. Almost like a painting, depending on how smudged the grain is when you cancel it.