Are all kind of ads bad?

I had a recent convo with a friend after we played this one game, so apparently it's a game where you normally pay to get keys to unlock part of the map once your free daily ones are gone. Or, you can watch 5 30 sec ads to get 5 keys.

Now, I was wondering what if this was used in an app that touches finances. Like watch a 30 sec ad get 10 cents of value, that can only be used in the app. This to me sounds like something a user would enjoy, I would. My friend just said everyone hates ads, so he doesn't think it's a good idea.

But if you can get actual value from it, say a retailer does it, those cents can go a long way no? If so why aren't some companies making us watch ads despite a subscription, and make irritating if they can give micro rewards as well for choosing to watch? Wouldn't ppl don't mind ads then?