What is a sutra?
The longer version of the Heart Sutra conforms more closely to the format in which Buddhist sutras have been recorded and presented. As Ken McLeod points out (see Ashoka course), Buddhist sutras bring together the Buddha’s mind and the seeker's in stories. These stories have a structure.
After setting the scene, the sutra usually begins with a question.
A sutra is a question and answer session with a teacher. The teacher was often, but not always (as with the Heart Sutra) the Buddha.
Sutras usually have three elements.
In the sutras, when asked a question the Buddha answered in four ways — depending on the nature of the question and the questioner.
The sutras are not intellectual or scholastic texts. They are a record of an interaction between a student and a teacher.
If you seek to find logic in them you will miss the point.