I feel like my expectations were incorrectly set by the verbiage used in their advertisement, website, and within the tool itself.
Often, they mention "preventing" fraud and telling you how much money you've "saved".
However, that's not directly what this tool does, nor is the money saved more than an estimate. It adds in negative IP addresses AFTER a visitor has been identified as being likely fraudulent. This means that you will have to pay for the first click in each case, and the savings are the future clicks that would have occurred from that same IP address.
Additionally, there is the issue that Google imposes a limit on the amount of negative IP's that can be added and they expire after 30 days, so the negative IP's that are added are inherently useful for a limited-time only.
Therefore, again, I believe it is very important to point out that the money saved is an estimate only, and the real figure could be a lot lower. My biggest constructive criticism would be to make it more clear to the user that the "saved" figure is not based on actual numbers, but rather on projections (and I'd love to obtain more insights into how exactly this projection is calculated).
I will continue to use the tool for the time being, as I hope that I am wrong, and that there are some real-world savings and improved Google Ads performance. As of this writing, after 13 days of use, I have not seen any numbers in my Google Ads account that indicate an improvement in performance as a result of using Fraud Blocker, but I will keep an open mind.