Well, yeah. The real advantage is only having a single file to transfer, makes eg. SFTP a lot less annoying at the command line.

Lossless compression works by storing redundant information more efficiently. If you've got 50 GB in a directory, it's going to be mostly pictures and videos, because that would be an incredible amount of text or source code. Those are already stored with lossy compression, so there's just not much more you can squeeze out.

I suppose you might have 50 GB of logs, especially if you've a logserver for your network? But most modern logging stores in a binary format, since it's quicker to search and manipulate, and doesn't use up such a crazy amount of disk space.