[abdullahkhalids]

Imagine a static website that provides crucial information, for instance, some regulation you have to follow. Your enemy MITM attacks that website and sends you a different page, which gets you in trouble.

The certificate guarantees that the information you are getting is from the entity who actually has access to the server serving the website.

[woodrowbarlow]

even if you have something like a "donate" link that's goes to a third party payment processor. a MITM could redirect that link the their own paypal collections page.