So as far as possible, CPython only uses __lt__ ("<") element comparisons for its order-sensitive algorithms.  This is documented for list.sort(), but the bisect and heapq modules strive to do the same.

The point is to minimize the number of comparison methods a new type needs to implement to participate (and "just one:  __lt__" is ideal).

Your change would require they implement "__le__" too, so is unlikely to be accepted for CPython.