The root technical issue here seems to be that the IPv4 space is fundamentally pretty small and easy to search, the browser just uses a crc32 to obscure the loc

The root technical issue here seems to be that the IPv4 space is fundamentally pretty small and easy to search, the browser just uses a crc32 to obscure the local IP address, and you can write code to brute force it with a little sophistication. The security impact, as others are pointing out, is pretty minimal. Knowing a local IP address behind a NAT isn't "not" a privacy issue (e.g. I can see things like gaming anti-abuse using tricks like this to discriminate users who need to be blocked vs. normal players), but it's not much of one.