It solves problems I personally have my own workarounds for:
If a tab is "distracting," I close it unless I'm going to read it this session (conveniently these have red italics - I think I have Tab Mix Plus doing this but I don't think it's required for this function)
If I want to read a tab sometime after this session, I use Read it Later
If I want to open multiple tabs at one time, put multple bookmarks in a folder and middle click the folder.
If I want to open tabs by clicking on a thumbnail, I use Speed Dial
Furthermore, it re-creates the problem I had before discovering "Single Window Mode" in Tab Mix Plus, that of having to look at multiple windows to figure out which window contained a specific tab.
EDIT: Also in the shopping example they give in the video, a good solution for that is the way IE8 gives the tabs opened from the same source their own color automatically. This can be emulated in Firefox using the Vista-Aero
theme, but I wish they would extract that functionality into a separate add-on so I could use it without making Firefox look like IE.
I may change my mind when I get around to testing it, I'm just not that motivated to install yet another build of Firefox to give this a try. The "tab dashboard" idea might get some use if I don't have to recreate it from session to session.