I also enable & use it with languages it doesn't really have proper support for (like sql and ruby) - just add words to the dictionary as they come up.
I came here to recommend the same.
This has saved me from sooo many silly mistakes.
English is not my first language, or that of many of my colleagues, so it's very easy for spelling mistakes to slip into the code.
And very hard to correct after it's part of the codebase...
The main annoyance is that the dictionary is directly inline in your main json config file. It's around 50% of mine right now. I wish there was a way to refer to an external file.