The matrix (and its corresponding rules syntax) in uBlock Origin is not as powerful as in uMatrix. In uBO, you can specify how to handle traffic between two origins. You can also choose which type(s) of content can be loaded from a particular origin. However, you cannot specify both at once. For example, you can't create a rule in uBO to allow only image requests from google.com to googleusercontent.com.

The uMatrix rule syntax can do this, and the matrix UI does provide this capability.

EDIT: formatting, typo

> For example, you can't create a rule in uBO to allow only image requests from google.com to googleusercontent.com.

Sure you can:

  google.com googleusercontent.com image block

See https://github.com/gorhill/uBlock/wiki/Dynamic-filtering:-ru....

The only reason you'd use uMatrix is if you create rules that can't be done with the matrix frequently enough.

That doesn't work for me. If I enter that rule into the "My rules" editor, and click the "Save" button, the rule is immediately deleted. Also, the documentation you link to entirely confirms my assertion that you cannot combine type-based and hostname-based rules. For example:

    Note that with type-based rules, the destination hostname is always *, meaning "from anywhere".

Oops. I was wrong.

thank you, i'm going to try it