It certainly helps, go for it. The MSc is only one year anyways, so, can't you give up one year of "good time" for something you'll be proud all of your life and will help you later on? The distinction, however, is not the only factor when considering admission. I got mine and my current supervisor told me that without work experience he wouldn't have considered me. Another of his students didn't have distinction but managed to get in. And even another student had a distinction but failed to proceed to 2nd year.