Sure. I use multiple browsers each day for various reasons. It's hard enough keeping bookmarks synced. Top site pages are also largely useless in that they only keep the most visited pages. I have numerous work pages I visit often that get placed at the top. Numerous news pages, numerous blogs. In each case, I'd rather have some form of context.

For example, I don't need the dial telling me about HN, Reddit, ArsTech, and other tech news sites individually. At the very least, I'd like to just select news sites, and have the browser deal with it intelligently.

The dial is useful, don't get me wrong. But it's far shy of a replacement for bookmarks.

I realize I also might be the exception to the rule. =)