So now you can place ads for your app to pop up in search results.
I don't like this move. Because it changes the chances of developers to make it in the list of search results. The App Store's aren't a great place to discover a fitting solution. Now, the search results aren't even guaranteed to be 100% relevant.
If I had the money, I'd use Search Ads to try to increase my revenue. Without money, you're screwed, though.
At least the pricing sounds good: you pay for a tap and you can put a daily cap on your ad budget. So literally everyone can try to use Search Ads to increase the odds. The thing is that each tap is priced according to the market, though. If your competitors are willing to spend a lot more than you, chances are a limited budget will not make it:
You determine the maximum amount you are willing to pay for a tap on your ad. Using a second price auction, Search Ads calculates the actual cost of a tap based on what your nearest competitor is willing to pay for a tap on their ad, up to your maximum cost-per-tap bid, so you’ll always pay a fair market price. (Source)
Apart from the amount of fairness of pricing and other technical details, I find the very move to place Search Ads in the App Stores troubling in itself.