Sorry, but NameID does both, you're repeating work. You can log in using NameID to prove you own the Namecoin address linked to your Namecoin ID information. That's how it has worked for a while.
You're right but there's an important difference between NameId and BitID:
- NameID relies on OpenID which is a nice system but requires a third-party (the identity provider) to let you authenticate.
- With BitID, no third-party is required. It's just your wallet and the website.
Both systems have their strengths and their weaknesses. It's a matter of choice.
No, you're still misunderstanding, nameid.org just uses openid as an example, it doesn't rely on openid at all, it relies on Namecoin ID. The php source code for nameid.org is open, you could use that auth mechanism on your own website as is, without openid, or reimplement it in another language. It sends a message, you sign it with the key used for your namecoin id, the site checks the signature & logs you in. It works almost exactly like BitID, but pre-dates it & allows you to link it to your ID information stored in Namecoin.