Of course, practically speaking it doesn't just "happen" to block ads; that's a major motivation for its development, and so we usually just refer to it as an ad blocker.
To answer your question directly: if you want ads and no cookie popups, disable the ad lists and enable the cookie popup list.
Yes, at that point you may as well just install the other addon, but the uBlock method preserves a key advantage: the ability to combine multiple cookie popup block lists. This is useful in case several people are making lists that cover different corners of the internet.
I think that if I'm visiting a website and using its bandwidth, the website ought to get paid. If the ads are too egregious, then using the website isn't "worth the cost" and I go to a different website.
I do however pay for Scroll[1], and I use Firefox's Enhanced Tracking Protection. Due to the latter, many websites think I'm using an adblocker and complain, which really irks me.
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Only when you make a purchase based on an ad are you supporting anyone. At that point you should just buy the better product and support the website by sending them money instead of buying a shitty product that has advertising priced in.
