ALL websites should be designed in a mobile responsive way. No questions, ifs or butts. If your website doesn’t look good on mobile, it is a certainty that you will be loosing visitors to your competitors.
The shift in visitor behaviour has been noted and acted upon by Google in the last 5-10 years, and Google now ranks a website using ‘Mobile First’, which means that Google checks your website on mobile before desktop or tablet for any quality issues.
If there are issues, such as the content is too small to read on a smaller screen, or buttons are too close together, then you will be marked down and your competitors will be ranked above you.