When people started calling my personal mobile number with questions about a voluntary organisation I'm involved with, I was confused: we weren't sharing that number. It turns out that Google had decided to take the number I used to verify my identity for Google Business some years prior and start putting it in Google Search results. WTF, Google?
I expect the algorithm is a) not publicly published, and b) changes periodically - like to just require one click when a particular department needs to “make their numbers” by the end of the quarter.
I challenge you to find any “free and easy, one click” business listing that gets 0.1% of the visibility of a Google info business phone number.