Telling the browser to accept all self-signed certificates is a bad idea, because it&#x27;s no more difficult for an attacker to create one of those than the legitimate domain owner. Let&#x27;s Encrypt has at least two huge immediate benefits:<p>1) It does challenge-response domain validation from an external server. It&#x27;s not enough for an attacker to intercept and modify traffic between the client and server -- they also have to control the route between the server and LE. This isn&#x27;t an infallible check but it dramatically raises the difficulty of an attack, especially if the check is done from multiple independent locations.<p>2) LE supports Certificate Transparency, which means they verifiably log all certificates that they issue to multiple third-party observatories. Even if an attacker can bypass domain validation, they can&#x27;t actually get a certificate without immediately making it obvious that they&#x27;ve done so, giving the server operator the chance to revoke the certificate and investigate (if they&#x27;re paying attention).