What possibly value is there in coercing strings to integers for _some_ operations but not _all_? I can see rationales for always doing it or never doing it, but this seems like the worst of both worlds.
That's less a "rationale" and more a "cause," though. If adding quoted integers always treats them as strings, never integers, then allowing coders to subtract quoted integers as integers can only possibly lead to confusion. One or the other should be removed entirely (probably the second, but what do I know).