A good example might be PLU codes [1] on produce in North America. They're 4 or 5 digits, and employees of a grocery store usually know them by heart (they're in the "employee of a grocery store" domain). Customers, however, are interested in knowing what the vegetable or fruit is, not the code.��
So, depending on the application domain, #asString might print the code (for grocery store employees) or the name of the item (for customers).
Delving deeper, we find these codes even contain info about whether produce is GMO, organic, etc. which could also be used by #asString depending on requirements.