Pros of SQL (some only apply if using a primarily SQL-based system, so probably not to all graal servers
):
- Easy access to all data
- Made to store and request data (and has proven itself)
- Doesn't break from staff editing the attributes
- Better relational data management
among others
(Of course storing all data in NPC-flags is also a way, but then you end up having to write more potentially slower and buggier script code)