Which websites must have HTTPS encryption enabled?

With more and more emphasis on information security today, HTTPS protocol sites have undoubtedly become the mainstream. As it stands, the following websites must enable HTTPS protocol encryption:
* E-commerce platform and its related payment system website
* High privacy websites such as banking system and financial institutions
* Governments, universities, scientific research institutions and their related websites
* Websites with search engines as the main source of traffic
* E-mail-based enterprise communication platform