@luetage When you doing research on multiple but related different subjects, believe me you do need that.
Here is a simple scenario:
I have a set of opened pages related to say subject A, but now I am working on subject B, so all A tabs are hibernated.
However, subject B, has some dependency on subject A, so I need to go back to some page in subject A.
Doing this with sessions is cumbersome, firstly I do not need to load the whole session, secondly maybe I need to just take a fast glance (formula for say) that was on that page, thirdly I need to find that page in fast glance, not digging inside the my sessions.
Hope this clarifies the situation.