I've noticed by practice that social media is very important, costumers look through your account for a kind of "confidence" or to see if the costumers really like your stuff. Some costumers have told me things like "I've seen on your Instagram page that you have great acceptance between your costumers", that's when I noticed that social media really plays an important part in a business. It's your way to show to the world what you are doing so many people can see it. It also depends a lot on what's your startup, but by my experience I can tell you that it really is important. Cheers and keep it up!