According to article above not only you will sell better by having better conversion rate, but also you can save efforts as you don't have to triple website versions for desktop, phone and tablet, so it seems to be a very practical approach where it applies.
Our website isn't responsive but it loads a mobile version on smartphones such as iPhones (depending on the screen size of the smartphone/tablet). We have however turned "off" the mobile version for our WHMCS integration - purely because it loads far too cluttered on a mobile version I found.
First, look at your traffic stats to see who or what is viewing your site. If 99% of your traffic is from a computer with 1% from mobile, don't waste money. If the percentage is a good number for mobile, then make it responsive or responsive enough.