The SSL certificate or https protocol is used for encrypted data transmission between the user's computer and the web server. Without this encryption, data can be spied on more easily by anyone who has access to the data network. More information at Wikipedia.
HTTPS means "Hypertext Transfer Protocol Secure", was developed by Netscape and published in 1994 for the first time with the browser "Netspace Navigator".
In the past, SSL-encrypted connections were only used in social networks such as facebook, Google+, Xing or Twitter, online shopping sites and banking or even e-mail accounts. Today this is very different. Especially since the entry into force of the DSGVO in Europe, almost every small website operator uses an SSL certificate. In my view, it is only a matter of time before SSL is completely normal and hardly anyone talks about it.
No. There are still use cases, or countries and regions in the world, where it is not legally questionable to use SSL encryption. From my point of view, there is no reason anymore to not use encryption. Why should one give security up? After all, every modern web host offers free certificates from Let's Encrypt. These are usually sufficient for most applications.
Normally you have to set up your own certificate. A good provider, such as A2 hosting in the US offers easy-to-use interfaces that allow you to embed a SSL certificate from Let's Encrypt for free.