Role & User - Inheritance?

[GENERAL] Role & User - Inheritance?

A ROLE dba01 has been given the option of SUPERSUSER.
A USER user01 is created and tagged to the above ROLE dba01.
When attempting to create a Tablespace (logged in as user01) it generates
the following message:
"permission denied to create tablespace (tblspc01). Must be superuser to
create a tablespace.".
Since user01 is tagged to dba01 (who has the SUPERUSER option) - should'nt
user01 also inherit this? If not - what benefit exists in grouping users
under a Role?

Cheers!

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