{Till some time back|Till few years back" no one bothered if your website was using SSL or not. Infact the term was not known to many and very few knew about the trusted seals offered by security companies. If you had an SSL certificate you were considered to be someone who was overly cautious about securing website.
This all changed SSL for Website with a Feb 2018 when Google came out with a update for Google Chrome and on its search engine prefering ranking to websites that were protecting their clients via HTTPS.
Google Chrome and subsequently all the other browsers started tagging websites which were not on HTTPS as insecure.
Need to know why you need an SSL?