I think it’s early days for Maker Pipe so I’m not going to dunk on them too hard for this, but I noticed the lack of angles means you can’t build for instance a 3:2 rectangle with cross braces to prevent racking. You have to do squares only. Kee seems to have solved that problem.
I am just wrong due to incomplete info. The page I originally clicked on only had about half of the full catalog on it, and the way it was constructed I presumed it to be exhaustive.
There’s a 180° adjustable fitting that does exactly what I described, as a sibling to the link you provided.
