It's beneficial for the company because it receives both advertising and sales leads that it wouldn't necessarily be able to access otherwise. It's also beneficial for you and their other affiliate publishers, who are able to make money from sales without actually having to get involved in handling the transaction. Since all you're doing is essentially connecting people with products, affiliate marketing can be one of the most time- and cost-effective methods to make money online. (See also: 5 Ways to Make Passive Income Online)
My business, Pure Residuals, was developed and launched in July of 2013. It is my primary website, but one of many over the previous 10-15 years of earning real money online. I have made thousands of dollars selling other peoples' stuff for fantastic commissions and I truly enjoy doing it and teaching others how to get started and eventually become a full-time online marketer.
If the answer to each of these questions is a resounding yes, rather than jumping to conclusions immediately, take time to research whether or not others are out there making a sustainable affiliate income from products and content in this niche. In a sense, competition is a good thing here—it'll help you validate your idea and prove that it's worth of building a business around.