Put yourself in the shoes of your customers and just imagine for a moment that you are on an e-commerce website and you are about to purchase something and BOOM!, a message telling you that the site isn't secured....would you put your card details...NO
That is the benefit of SSL...
You want to protect your customers? Use SSL
You want your site visitors to trust you? Use SSL
You want your website protected? Use SSL
Can a site protected by SSL be hacked? Possibly YES
People use SSL for the dumbest things like a simple one article website because Google made us to so people don't get stupid alerts. But when talking about ecom, online transactions, people personal information.. SSL is a must to encrypt all transferred data.. so do it, it's free nowadays anyhow. Use cloudflare if you don't have the Let's Encrypt option in your hosting panel.
Yes, it is important. Over the past few years SEs (Search Engines) have been placing more emphasis to secure sites (sites with SSL Certificates) in their effort to secure the web. Do note that having a secure site is just one of the hundreds/thousands of variables SEs look at.
Aside from that, it's beneficial to have because a lot of default browser functionality these days will warn a visitor if a site is not secure.