I understand the apprehension in this community about ads in general but when it comes to search engine ads, it does add value (and relevance improvement) to many "commerce" oriented queries.
Google also already knows categories that generally don't get high ad engagement and doesn't show them for those. An example would be "chuck norris biography" - the intent is clear that you're looking for information primarily and even though I'm sure Amazon or others buy tons of ads against "chuck norris movies", etc. Google is smart enough to know not show you those irrelevant ads.
I don't believe that I've ever clicked on a text ad. (That is to say, I had never clicked on one prior to starting using an ad blocker two years ago.)
If I'm attempting to research a product or product category, I'll go to an aggregator like Gdgt or an editorial site like The Wirecutter.
I can't comprehend why one would ever click on ads when intending to spend money. The last source I would ever trust to recommend how I spend my money is an advertising platform.
Google also already knows categories that generally don't get high ad engagement and doesn't show them for those. An example would be "chuck norris biography" - the intent is clear that you're looking for information primarily and even though I'm sure Amazon or others buy tons of ads against "chuck norris movies", etc. Google is smart enough to know not show you those irrelevant ads.