"Which has the side effect of requiring you to input a captcha every time you quickly want to google anything" - this is a common scenario not with AN but in scenarios when Google doesn't have much data about you - a fresh setup, no Google cookies, blocking cookies, Tor browser etc. AN is orthogonal to that - it simply "clicks" ads, bringing Google more money at the expense of advertisers. I use AN on several computers and observe no above-mentioned side effects when Google has enough data on you. When they don't, they will show the captcha. So it's orthogonal to AN.