What's the difference between firefox containers - part of core and this ext?

[artfulrobot]

Hi,

In my memory, I've used this extension since before containers were a part of core firefox. But now they are, and they have many of the features of this extension, it would be good for this extension to clarify what it does in addition to what you get out of the box.

e.g. containers, manage-containers, colours, icons (limited set): all in core.

The only thing I've found missing in core is "Always open in this container".

Can anyone clarify this situation? I'm also confused why Mozilla would add some pretty functionality in this addon not in core and maintain the two separately?