On Twitch, advertising arrives by two routes. One of them AdSilence catches like anywhere else. For the other we would rather explain how it works than promise something.
Everything Twitch loads as its own request — ad space next to the picture, overlays, measurement points — is in the lists AdSilence ships by default.
Twitch splices part of its advertising directly into the video stream. To the browser that is the same request as the stream itself: there is no separate address left that could be blocked without taking the video with it.
Because a blocker that promises something and does not deliver after installation costs more than it brings. What AdSilence does on Twitch is above — and so is what it does not do.