The main thing you must remember is that a fingerprint cannot be reproduced as a number - it’s way more complex than that - so this is why it is not possible to use for a number based login like SambaPOS has.
That statement isnt entirely true and this can be done
When i was teaching our school canteen pos system used fingerprints, every student had to have their thumb scanned so that when purchasing food scanning their thumb on the pos opened their account to pay for their food
I got talking to the guys who set it up and they said the way it works is that the fingerprint is never stored, it converts the print into numbers for data protection of the kids and this number is all that is stored. You also cannot create the fingerprint by using this number
When the kids scan their print to display their account it doesnt search for a match of a print as it doesnt exist it, it converts their print to a number and matches that number against the saved number for the student in the database to open their account
So it can be done but im guessing its extremely costly due to having all the data protection stuff needed for schools