Decoupling your physical mailing address from your office location makes a lot of sense, since changing the address would be very disruptive. Same reason you'd use Google Voice over giving someone your direct number.

And more and more companies these days don't even have any fixed physical offices, with remote-first cultures. What's the address of Trello? You won't find it on trello.com

It's not like you're going to actually walk there. If it's a legal address registered for the company, that's enough for every interaction you need with them.