Calling HLists “collections” is misleading. In spite of their name, HLists are actually record types. The only actual list involved is a compile-time list of component types used to form a record type.
To give a perhaps odious but relatable analogy, a form is a list of questions, but a filled form is not a list of answers - it is a record of answers to the questions in the form.
To give a perhaps odious but relatable analogy, a form is a list of questions, but a filled form is not a list of answers - it is a record of answers to the questions in the form.