I run a marketing solutions company and we've been buying Google Ads for over 10 years. Of course, Google knows the identity of the Advertiser. If Google wanted to, it can also verify some or all of the ID by using the bank account or credit card information submitted by the Advertiser. (For the uninitiated, it's impossible to set up a Google Ads account without adding at least one funding source). But what Google is doing with its new measure, I'm guessing, is seeking additional info like incorporation location, making the advertiser info public, and simultaneously giving a chance to the advertiser to clean up their accounts, if required, and submit the info regarding name, address, incorporation location etc. that they want their prospects and customers to know them by. For example, when I set up my Google Ads account, it was in my personal name. Even if I subsequently run my company ads on the same account, it doesn't matter since the ID is between me and Google. But, if my ID is going to be shown to the public, I'd rather change the name to my company name, which is how I want my ad to be seen.