By coincidence, I've looked yesterday a small documentary [1] about the people tagging all those invoices to train theses models. For 120 €/month they are reading about 1000 to 4000 invoices per day and check and tag them for AI training. [1] https://www.arte.tv/en/videos/126831-000-A/arte-reportage/
In my neck of the woods, B2B invoices are now required to be delivered over the Peppol network in UBL format, which further improves reliability.
Doesn't necessarily eliminate the need for an accountant, because the chosen UBL standard has lots of room for interpretation and ambiguity, and it's impossible to uniformly decide how process an invoice based on the invoice alone (e.g. is this deductible? is this even a business expense at all? which ledger should this go in? etc).