Yes! My side project turned into my day job several years ago but to this day one of the largest source of income it brings in is from ads. I now use more of a niche ad network provider to serve our ads but at the beginning everything was google adsense. While its true that day 1 ads didn't generate enough to cover costs but since I self hosted and worked hard to optimize everything I didn't have huge AWS bills to pay and costs were really low anyway. It was only six month ago that we finally made the jump to the cloud.

Anyway the point is, at least if you're not targeting an user base that has ad block enabled, ads, and I'm not talking about annoying ads, still can work just fine. What we do is offer our users a fairly cheap subscription option to disable the ads too along with getting some extra features so a lot of people jumped on that too... but I love being able to offer most of our services to everyone without any cost so thank you advertisers!