a use case for __array_interface__ "scalar" path?

Hi,

I was trying to prevent array creation from iterating over instances of classes implementing __iter__, __getitem__, __len__ etc. 
An effective way (at least with a UserDict subclass) seem setting 

__array_interface__ = {"shape": (), "typestr": "O"}  # with data field omitted (!)

According to the docs https://numpy.org/devdocs/reference/arrays.interface.html#object.__array_interface__ 
"Not specifying this field uses a “scalar” path that we may remove in the future as we are not aware of any users." 
I am new to __array_interface__, so this might be a bad approach (*). If not, this seems to be a good reason for *not* removing.

Note there is demand for avoiding coercion of custom types into new dimensions:
https://stackoverflow.com/q/43722023
https://stackoverflow.com/q/70460738
https://stackoverflow.com/q/22290204
https://github.com/numpy/numpy/issues/27212
https://github.com/numpy/numpy/issues/27382

(*) Still, other attempts partially messed up with class functionality (e.g., __len__ = None) or did not work at all:
__iter__ = None (TypeError: Could not convert object to sequence)
implementing __array__ (RecursionError: maximum recursion depth exceeded)

Cheers,
Marco
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