I have a fairly extensive bookmark list--extensive enough that it is cumbersome to use: it is longer than my screen, which is in portrait mode. On the other hand, I use tabs all the time, and I might have sixty tabs open because it's easier for me to scroll across the tab bar than to try to find things in the bookmarks menu.
It would be even easier if the tab bar had folders for types of tabs, as I don't need anywhere near all of them all the time. For example, I could use a tab folder for utility/banking/financial login pages; one for insurance/medical login pages; one for word puzzle pages; one for dictionaries. They would open in a new tab.
I should hope that such a thing would be more durable than the actual tabs, as the bookmarks menu is; in the past couple of days all of my tabs have been obliterated twice due to some Firefox tantrum, which has goaded me to post this.
A few notes: My computer is in my home, so I have no concerns about secure access to sensitive tabs. I am somewhat visually-impaired, so minimizing head and mouse movements would be advantageous to me. I use Pocket for pages that intrigue me, but I don't see its viability for this purpose, as it goes elsewhere.