I've removed your link because it wasn't necessary to answer your question.
I'd say that you may be asking this question if only 5-6% of your traffic came from mobile devices but with a 30% the answer is really: Yes, of course it is!
But even if you only had this 5-6% of traffic from mobile devices, I would still answer yes although in this case it wouldn't be mandatory. The reason is that it is better to be prepared for the future and better safe and sorry. And if there's something that we know is that mobile devices are a growing number (in number of devices and in number of visitors to our webs)
Also, especially if you're living or want to live from designing/building websites, using the latest technologies (if it make sense, of course, not for the shake of showing off) and trends that will likely remain for a long while (this is the things with trends, you never know what will stick but...) will benefit you. Your image as a designer/developer will be of one well informed of the most efficient ways of using those technologies and that knows well his job.
Probably, you'll see an increase of your traffic once you've redone your site using a responsive method.