Whilst there's a good, solid background to support silent magic, there's no doubt that patter and presentation, be it comedy or dark and serious, can really make (or break) a routine. It also helps to spin a shorter routine out a bit and allows the narrative part of the presentation to involve the audience more than just showing the routine to them. I have no doubt that very few members of magic audience even begin to believe much of what is said but they go along with it because that's part of the deal and they're listening to a good old fashioned story being woven and told - shades of the tribal gatherings around the fire after evening meal etc.
Some performers prefer to work out a script and stick to it because it helps to plan the effect and cues in the various moves at the right times. Others will have a broad outline of what need to be said and will ad lib as much as possible to keep the whole thing as fresh and new as possible. I don’t think I could stick verbatim to a script - I once sat and listened to a comedian doing the same act four nights in a row and every word was the same. Boring as hell after the first night but very funny for those hearing it for the first time.
This is only a personal preference but I much prefer the narrative story telling type of routine and there's a feeling of having seen a well rounded and fully entertaining evening rather than just sat through a performance of a lot of excellent tricks. As you mention, Derren Brown revels in patter and presentation and we've commented on several of his 'in-jokes' before now. Indeed, Mentalism wouldn't work very well without patter even though supposed to involve mind to mind communications without the need to verbalise! Penn & Teller are also worthy of inclusion here - one is always mute but the other never seems to stop talking - a great contrast and it works very well indeed. Houdini always liked to ramble on a bit during his stage shows but with the reedy voice and rather heavy accent, perhaps he should have stuck to the silent stuff? Another style would be that of illusionists such as Franz Harary who seem to spend some time describing the setup and intention of their effect then abandon the mike and just go do it. I suppose we have to include David Blaine in here somewhere but I'm not impressed with his voice and tone, loads of ,' Here, here, let me show you, no, come back, I wanna show you something, hey, look at this'. Stunning stuff, Shakespeare must be very jealous

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PS Then again there's the sort of patter which Jerry Sadowitz uses - I wonder which category that falls in to

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