It depends what you mean by "secure".
It's encrypted, because you've told it to use HTTPS (HTTP + TLS). If the remote end doesn't talk TLS, then the two won't be able to establish a connection at all.
However it is also insecure, because the client has no way of knowing whether the remote device is the one it's expecting to talk to, or an imposter. If it's an imposter, they can capture any data sent by the client, and return any data they like to the client. It's the job of a certificate to verify the identity of the server, and you've told it to skip that check.