A mobile responsive website is important because when potential customers use their phone to make a Google search and they end up on your website you want them to have a good experience. A non-mobile-friendly website does not load properly on a user’s phone, this causes them to get frustrated and leave.
A good user experience is also important because Google will know how your users react to such a unresponsive site. This will cause Google to rank you lower than your mobile-responsive competition.
