More verbose languages like C++ become less obnoxious to write in. I know RSI has been mentioned and any tool which cuts down on excessive typing will help with that.
It sometimes reveals bits of the standard library I wasn't aware of in unfamiliar languages. I can write my intent as a comment and then it may pull out a one-liner to replace what I would have normally done using a for loop.
The main downside I've observed is that if I'm not trying to reign it in, it can result in a lot of WET code since it can pattern match other areas of the surrounding code but can't actually rewrite anything that has already been written. It is important to go back and refactor the stuff it produces to avoid this.