It's actually pretty common for people to want to denoise, then put a little film grain back in afterwards. Film grain <> noise.
The reason you see "grain" when you watch film is that that's what the celluloid is actually made out of. It's not an overlay. You see it more on dark areas and less on bright areas. GrainFactory is one of the only plugins I know of for AviSynth/Vapoursynth that does a pretty good job imitating that and looking more genuine. So it's worth it IMHO to have it for AviSynth as well.
If you're only going to put one in at some point in the future, I'd probably go with the last one (GrainFactoryLite_v1.2.avsi) because it has the best precision and finest control. Most people don't use the "texture" options anyway.
The reason you see "grain" when you watch film is that that's what the celluloid is actually made out of. It's not an overlay. You see it more on dark areas and less on bright areas. GrainFactory is one of the only plugins I know of for AviSynth/Vapoursynth that does a pretty good job imitating that and looking more genuine. So it's worth it IMHO to have it for AviSynth as well.
If you're only going to put one in at some point in the future, I'd probably go with the last one (GrainFactoryLite_v1.2.avsi) because it has the best precision and finest control. Most people don't use the "texture" options anyway.