Plain and simple: You need to be seen by anyone on any device flawlessly NOW.
Make the best first impression irregardless of the individual users device. A recent Google report reveals that over 60% of search engine traffic is now originating from mobile devices. As a result, Google will drop you like a rock if your site isn’t "Mobile Friendly" by their definition. Here's Google's tool to test your site (or any site) https://www.google.com/webmasters/tools/mobile-friendly/ for mobility.