Those directions are for someone who backs up their iOS devices through iTunes. If you decide to backup through iCloud, you can delete the iOS backups on your computer. You do one or the other, not both at the same time.
Of course, if you use iCloud, it's most likely going to cost you money, as you will exceed the free storage limit.
I recently installed an external Thunderbolt SSD which is now my boot drive, everything from my internal drive was cloned to it. I want to move my iPhone backups back to the internal HDD so they don't eat up space on my external SSD. I tried the code listed here but it's not working. When I entered the code, Terminal said "The file exists", but it's still writing backups to the external drive. Here's the code I used:
ln -s /Volumes/Macintosh\ HD/Backup/ ~/Library/Application\ Support/MobileSync/Backup
Where am I going wrong?