Suggestion to use some form of document question answering to suggest values for custom fields

With document q&a the user could append a question to a custom field which is then passed to an algorithm.
This algorithm can then provide one or multiple answers for the user to choose from, or alternatively automatically fill in the field.

I have seen a few demonstrations of this, but I have not seen one that uses something similar in a proper project.
Examples are:
- https://huggingface.co/docs/transformers/main/tasks/document_question_answering#document-question-answering
- https://github.com/tstanislawek/awesome-document-understanding#document-question-answering
- https://github.com/Xyntopia/pydoxtools

pydoxtools is the implementation I tested personally, and I was extremely surprised how well this worked.

Is something like this feasible? I could see this being a huge help for most applications (i.E. finding a suggestion for the total amount to be payed for invoices)

The advantage I see over other implementations (i.E. the implementation from https://konfuzio.com) is that this way you are not restricted to the same document type/ document layout when searching for a custom field's value.