Correct. What you have been doing up to this point is just having Kodi directly connect to your PC. This is fine if you have plenty of headroom but it is not as fast as letting the operating system handle the task. You can mount (make a folder in the Linux file system point to your network share on your PC) your media via the OS and then point Kodi to that mount. So instead of Kodi opening something like smb://PC/movies it would point to /mnt/movies.
One way to do this is by editing a fstab file which will make this mount when you boot up and it will stay there. Another is with something called audofs. That one works similar to fstab, but it will disconnect and reconnect as needed. This makes it more reliable if your network share isn’t always available (like your wifi cuts out on your PC). I would just stick with SMB/samba and forget about nfs. A guide is found here…