There are game-play advantages to getting TotSC as well.
JOTTOMHACMIIAW: (just off the top of my head and correct me if I am wrong
)
Un-identified magic things are marked in blue.
The XP-cap is moved up to 161.000 which is great if you want to export to BG2
you can stuff more arrows, potions and so on into every slot.
You can see on the world-map how long traveling will take.
Durlag's evergreen resting grounds for lots of dead adventurers!!