Absolutely. I have two main use cases for text expansion.
There are things we type all the time. It's great to be able to type them in just a few characters. For example, I moderate on another website where I am frequently reminding people to do certain things. Having "canned messages" saves me a lot of time. I also use gmail's canned replies in a similar fashion. When someone emails us because they won in the weekly book promotion, I reply with the "canned reply" of our form letter explaining what happens next. The advantage of gmail's over a text expander is that it is shared amongst everyone who checks that shared gmail account.
Not having to look up information
At work, I have a phone bridge that I use for meetings. I have it set up so I can type myBridge and have it expand to the phone number and bridge code. I could copy/paste this information from somewhere. But then I'd have to context switch. Having it automatically enter saves me a tiny bit of time. And that adds up.