They do as most newspapers are not free at the newsstand. To get those local classified ads you have to pay.

They can be a negative or positive depending on the ad and when/where you see it

Some people love to see new products and ads show those.

Yep, back when I was into photography (which was well before the web existed) I would buy photography magazines mainly for the ads. Same with the Computer Shopper, it was almnost entirely ads and people paid for it.

There are some free ones but they're also 90% ads :p

Then again I used to subscribe to tech magazines back in the day, and you can think of the articles and reviews as well thought out and curated ads. (At least the good magazines).

My regional local paper (where “local” means “it’s headquartered in a town of 20,000 people 100km away from myself and has a catchment area of maybe 50,000 people”), titled The Weekly Advertiser, is consistently almost exactly 75% ads by surface area (measured on a few different occasions).

They're immensely useful and important for business owners.

(Just wait until you become a small business owner and get to experience the advertising landscape from the other side.)