Without TLS, sometimes still referred to as SSL, a webite's content can be modified by anyone controlling the network path. This includes ISPs and WiFi operators.
Sure, your website may have unimportant stuff on it that nobody relies on, but do you want visitors to see ads in your content that you didn't put there?
Sure, your website may have unimportant stuff on it that nobody relies on, but do you want visitors to see ads in your content that you didn't put there?