I used to do that at work with a couple of phrases I needed all the time but after we had a software upgrade I could never get it to work again.
What I did instead, because I really did need the phrases all the time, was put them into a word document and save it. I kept the document open all the time and would just go into it, copy the phrase, and then paste it into the email I was sending. It saved me a lot of time as well as typos.
As someone else mentioned, if it is something you just want in an email signature, you can set up a signature to go with all your emails.