If you know while writing the code what attributes you want - why schould you choose a prefix that interferes with your names? Why should you choose a specific prefix at all if you dont put loops into another? Note it still remains "sequence" until specified.
Because maybe someone else chooses the names of the properties, and does so after youve finalized your logic (whether it be dtml, or PythonScript). Maybe you want to make your logic robust even if that other user is malicious (or just really accident prone)
What if one chooses "sequence-item" just for the sake of example? ;)
Damn. I was sure it didnt allow hyphens in property names. IMO the *real* answer is to not implement logic in dtml. The problems (and the need for this patch) go away.