The design challenge
In order for any letter to connect perfectly to any other letter, many compromises had to be made. For example: Rounded letters couldn’t actually be round at the side. They needed a flat part which could then connect to the adjacent letters.
Some letters needed quite an unusual design to allow connections with any other letters. Have a look a the lowercase z for example. And letters with a lot of white-space actually needed to contain a stroke for the next letter. Have a look at the uppercase P or T as an example. But this meant that the design wouldn’t work well when the letter needed to be used alone or in an uppercase-only abbreviation for example.
Yet, with all these compromises, I think the fonts work very well when used.