You’re assuming that 1) the value of a username or URL is higher than the value of privacy 2) people use those for discovery. I’m sure 99% of social media connections happen via recommendation algorithms, friends-of-friends or search by name (not username), never directly typing a username or profile url.
You're sure about that? I don't think so. There's tons of connections made from people transferring short, human-readable handles. Think business cards, word of mouth.
e.g. I'm at (@) handle. That's much easier to lookup as opposed to searching for someone's name. It may even be a business that's not tied to the individual's name.
