I do agree with could improve the documentation for the binding directive - it does leave you a little unclear what it's actually for.

I'm reluctant to start listing every individual thing that binding=False disables/breaks. Mainly because there's a lot of them. And because it's not actually deliberately disabling features - it just isn't using our nicer wrapper class. The better way of thinking of it is:

• binding=True behaves more like a Python function in almost every way,
• binding=False reduces the code size a little.

I see, cool.

By the way, does binding=True result in slower function call in general? ( sagemath/sage#26254 says that there is a performance degradation which I assume is what they are mainly concerned about )

I haven't actually measured it in recent memory. I wouldn't be surprised if it was a little slower, but probably pretty close on versions of Python that support vectorcall.