If your website is asking for any personal information it is going to need an SSL certificate. Without SSL, your site visitors and customers are at higher risk of being having their data stolen. Your site security is also at risk without encryption. SSL protects website from phishing scams, data breaches, and many other threats. Ultimately, It builds a secure environment for both visitors and site owners.
Not utilising an SSL certificate can cause your site to be flagged by browers, scaring away visitors - even if they do get through they could be wary to reust the site due to the http connection.