[valbu]

Because that is completely different approach. When using TST extension then "tab" is like bookmark + history element and not in your short term memory. One of the advantages over those is that visual overview is almost instant and so much clearer with structured tab trees with long descriptive tab names. It reduces brain strain as I no longer have to relay on blind searches in history and bookmakrs menu, google and notes in documents.

For example when getting into some game then all the guides, tips, videos, maps, mods etc. are open below one master tab and it is very easy to go back there after every month or so, back and forward works on tabs and you are like exactly back in this moment where had to stop that time. One such subject domain can be like 50 or sometimes 100 tabs and if your interests and work over about a year revolve around 30 subjects then few thousand tab-s is quite normal usage. Firefox + TST works with max 7999 tabs so there is quite some room.

I think the easily manageable high tab count is not even the primary advantage for starters, the fixed tab width with vertical tabs is as tab label is always visible and usually horizontal screen space is wasted anyway. Then comes the tree structure advantages and then the paradigm change to tabs as usable history when tab count is high.