Google My Business becoming like Yelp in attempts to extort small businesses
reddit.com
reddit.com
This comment explains half of it - it's basically an antispam measure, akin to online services verifying using phone numbers. It's not perfect but it ups the bar for generating fake listings. https://www.reddit.com/r/smallbusiness/comments/kivs8k/is_go...
The second reason is that it helps prevent listings hijacking. Since any user can suggest changes to a listing, it's fairly difficult to distinguish between the owner updating to a new phone number/website, or a competitor changing them to point to their own business instead. Postcard verification allows the owner to claim their listing and have more control about whether their business information gets changed. I think it also lets them do things like respond to reviews, and probably their own edits go through faster as well.
In theory it's possible to hide your business address and only show up on Google Maps as a "service area" business. No idea how user friendly that flow is these days.
I agree that Google should allow addressless businesses as it biases their search but they are not at all doing the same thing as Yelp.
Google My Business is a Google maps profile. Of course you are going to need a physical address.