@osclassics
No, incorrect understanding.
Let's say I insert into keywords following: Alabama, Vehicles, BMW x5, Bremen.
Let's say I have 20 banners in same banner group.
When user will come to my classifieds and select region
Alabama to see listings from here only, our sample banner will be shown because keyword match.
When user enter to search pattern
"New BMW x5 turbo", our sample banner will be shown because keyword match.
When user choose only
Bremen city, our sample banner will be shown.
When user look into category
Vehicles, our banner will be shown.
Hope it is clear now