Why do I have a /home folder and do I need it?

The folder /home is part of the standard MacOS installation. Just because it's empty, doesn't mean that it's not needed or not expected by other processes at certain times.

If you're short of space, deleting parts of the OS that you think might not be used is unwise. User-added content is likely to be at least 10 times the size of the system files, so start there!