Many thanks @Kishore_Reddy ,
now this begs another question :).
The Campaign Members List can directly be segmented out of the Profile and Account schemas.
Now my ambiguity is that the Marketing Member List has all Leads and Campaign Members List has all qualified contacts (with consents)
I am trying to understand the possible significance of Marketing List. Any business example if you could suggest would clear my ambiguity.
Appreciate your feedback
Best,