I've been using the near-identical firefox extension that sprang up shortly after the feature was announced, and predicted it was a useless feature that had barely any use beyond flashiness.
Well it's been installed for a few months. I think I've used it about 3 times in that period, just because I noticed the icon.
viamatic foxpose - gives you a preview of all your open tabs (or what ns said).
i've used it quite a bit - but that's because i've got a habit of opening lots and lots of tabs while i'm trying to find about something, and then losing the most relevant one.
The functional issue is obvious I think - if you have millions of tabs open, the thumbnails get smaller, so finding the tab you want in the mire (which would initially seem like the point of the feature) actually becomes more difficult as the need to use it increases.
The tabs themself suffer from the same issue of course, but identifying sites via their text labels or icons never posed an issue for me.
The only time I go over 20 tabs or so is when I'm surfing porn.
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