It will still work 30 years from now! 300 years! 3000 years. There will be no strange error messages in the log, no browser updates breaking stuff.

Personally, rather than this luxurious approach, I just do one giant form and store all values in local storage. If something is wrong have one message at the top listing which fields failed validation and why. Generate some css to put a red border around the fields.

Local storage might not be a good idea for such sensitive data but if you can get away with the simplicity it's lovely.