I may not be correct either, but in my experience, on Windows, if not using Jitter, and if not using any image or movie formats that depend on Quicktime on the Windows platform for playback, you don’t need Quicktime.
What I don’t know is if *all* Jitter components need Quicktime, or just some.
MaxMSP and Jitter run alongside Quicktime. That’s how we made it all work. You may find that you can run some things without Quicktime installed, or with some versions of the codecs, but this is not something we have put any effort into studying, so there’s not a whole lot we can tell you apart from the fact that it’s unsupported.