Yes and no, if the github pages is served from S3 or other resource inside AWS network, then cloudfront would be safe.

And regardless of that it offers privacy for your users.

Beyond privacy it also vastly improve security too, since users are most likely to have malware and ads injected by an infected wifi router.

It also increases complexity of an attacker that has control of the local machine, since they'll now have to install a custom root certificate.

Nothing is perfectly safe, all we can do is raise the bar.