They ARE loaded with banner ads, and they are giving not just small but absolutely TINY amounts. The money earned from advertising is also quite small so I suspect they don't make much profit either.

I spent over half a year clicking and clicking and clicking on faucets, but if I added up all the BTC I got from them*, it would only be worth about $0.80.

There are much better ways to make money via the Internet. I wouldn't recommend faucets unless you're a beginner that wants to use them to learn how sending and receiving BTC works, or if the faucet has an affiliate program and you have a blog or something that might attract referrals.

*excluding the old Primedice 2 HH faucet, of course.