HN user
That's precisely what people do -- they design workflows that leverage AI to handle the forms that it can, and humans to handle the forms that it can't. And constantly retrain the AI based on what the nice humans just labeled. As the AI gets better less needs to go to the humans, but they're always there for the exceptional cases. BTW this isn't theoretical -- this is current best practice.
This technology is of intense interest to organizations that process thousands of forms per day. For example, the Internal Revenue Service, insurance companies, banks, etc. It is very much worth their while to optimize that processing, and they do.
The cloud services reviewed here are typically components in a much larger end-to-end process. They are valuable because they are fast, and work at scale.
Suggesting that the technology is useless because it can't parse a random set of 51 invoices misses the actual use case for which these services are appropriate.