Yeah, the code does much the same as the old numpy code (at least most of the same funny little things, though I seem to remember the old numpy code had something yet a bit weirder, would have to check).

To be honest, I do not know. It isn't implausible that the original numpy code dates back 15 years or more to numeric. I doubt whoever originally wrote it thought much about it, but there may be some good reason, and there is the safety considerations that people use the strides in a way they should not, which may trip us here in any case.