HTTPS is about 3 things, trust, security and privacy.
HTTPS helps prevent intruders from tampering with communication between your sites and your users' browsers. Intruders include both intentionally malicious attackers and legitimate but intrusive companies, such as ISPs that inject ads into pages.
This secure protocol also verifies the authenticity of the BOM website, preventing impersonation by malicious entities. Major browsers, including Chrome, label non-HTTPS sites as “Not secure”, which can deter users from accessing the BOM's services.
HTTPS encrypts data exchanged between users and the website, ensuring privacy.
Further reading
Lets Encrypt offers TLS certificates for free.