Forgot to address this:

> Is this some kind of USA mentality that use meter to define inch at the beginning but refuse to just use meter?

Probably yes, considering it was made in the US, using North American physical printing standards. I'm sure there's other software you can use that uses ISO standards.

It has been a while since I've used it, but IIRC, Matplotlib was made for print media, which generally doesn't use pixels, hence no pixel support. As you found, there are better programs to use with pixels.