Having an active SSL certificate installed on your website is not a “nice to have” any longer, it’s a must. It allows your site to be accessed over “HTTPS” (instead of the traditional “HTTP”) connection. This provides a level of protection against hackers.
As Search Engine Land points out, Google uses HTTPS as a ranking factor and started flagging sites that didn’t have HTTPS implemented as of 2018.
This is important because it means when visitors are sending information to you (think contact forms, quote forms, email sign up forms, purchasing item(s) from your site etc.) all of their data is encrypted — so the “bad guys” can’t get ahold of it.
If your website is still on the traditional HTTP connection, a hacker can obtain the information they are submitting on your website. Think of it as a middleman attack. Those bad guys have the ability to see your customer’s information in plain text view, right after it is submitted.