Welcome to my entire point: if the stride isn't going to change in any real-world system, why is the stride not part of the vertex format?
On the other hand, what harm does it do? I personally can't see any reason to change stride either, but the functionality is now there and maybe someone will find a use for it? I don't see it as being a "wrong thing", more of an odd but ultimately inconsequential decision. Doing what D3D does can make sense in many cases - makes it easier to port from D3D to GL, after all. That's gotta be a good thing. But in this case the D3D behaviour is also odd but ultimately inconsequential. It could be worse - just be thankful that it didn't take an array of each of buffers/strides/offsets like D3D does - that's painful to use.