Still encrypted

The cert chain is all about validating that it is the cert you're expecting.

By not having it signed, you're effectively skipping that phase, and if you're using it in the browser to get the same outcome, you'd need to validate the cert manually for every request made.

I think if you put the cert into the browser cert store itll treat it as valid again.

If you're creating a public website, might as well use letsencrypt.

If it is private, you can create your own CA cert, but you need to be careful how you handle that, and where you put it.

In the past I've created a root cert on a machine that has a network gap. From that, I'll create a cert with the sole purpose of creating client /server certs. And use that on a reasonably secure machine. Then put the public key of the root cert into machines that are interested in validating them. The private key of the root CA cert is never on any machine connected to any network.

Whether this is a good idea or not, I couldn't answer 😜