You can use keyboard shortcuts in many useful ways like 1. Email Signatures 2. Long Email Address 3. Words like "On my Way Home" and many more. it depends on your needs. HERE ARE SOME EXAMPLES
if you have many email address. for work and personal use. you can use a custom signature for your email address by just using shortcut commands.
NOTE: Since New Line (Enter Key) cannot be done in shortcuts. you can just edit and manually add a new line from each word. this is useful if you have long signatures.
Here's another useful example. specially if you have long emails that takes time to be typed.
HOW TO SETUP YOUR KEYBOARD SHORTCUT
Hope this Helps. FOLLOW ME and ill upload some tips and tricks for your Apple devices.