Create a database of custom fields per popular website to autofill common fields

I recently came across the custom fields feature and its ability to autofill those custom fields.

Instead of me having to inspect a custom field for a well known travel website to fill in my frequent flyer number, wouldn’t it be better to maintain this database in the code or API to auto populate these custom fields when I initially save my secret?

This way, I won’t need to even know about this feature or hunt down the ID. I would simply see the custom field populated in my secret, fill it out, and it would magically auto fill next time I’m logging into the website.