Very useful indeed! But I did notice a little problem. When I was in my Personal tab and span a child tab (also personal) to a Medium post as anonymous, one of my cpu cores goes up to 100% load.
That happen every time I spanned the Personal tab with this Medium post.
But, when I opened up the exactly same site on a regular tab (also as anonymous), the cpu was just fine.
So, I logged in at Medium in the Personal context, and the behavior was gone.
That happens on a Firefox Quantum in a Linux Fedora distribution.