There's nothing sus here; he's saying that the password managers built into the browser use a more secure model than a plugin that uses javascript to communicate with a web page. That seems to be 100% accurate.
If a Chrome dev had said we should use Chrome's password manager because Mozilla's in fundamentally broken, I would want more proof of that claim, but he did a fine job of explaining the vulnerabilities of a plugin versus a native manager.
This is about as low-key of a recommendation as you can construct.
Curious that he omits Safari though.
I may be biased though because I agree with the opinion. I use a combination of my browser's support and `pass`.