You’re promoting other people’s product. You don’t have to create your own.
It’s somebody else’s offer, you’re promoting their offer, and once somebody avails of that, you get paid.
If you’re spending $500 a day on Google Ads, maybe you want to make $600 here, profiting $100. But with the mailing list you’re also building to whom you’ll mail more offers, you’re going to make maybe an extra $300 a day, which is why it is the easiest money ever.