No, advertising is not necessary when a user can search a catalogue with multiple optional constraints, as we did in the olden days of printed catalogues.
Advertising is harmful - it’s somebody trying to persuade you that you need to buy a thing. First, you’ll usually know when you need something. Second, the salesman is not someone you’d believe normally.
It’s an interaction which normally should be initiated by you, not by sellers. Which makes advertising utterly useless immediately.