I have a good eyesight and still select 8 middle digits to make a verification contrast. Grouping is about memory, not eyesight.

I’m having trouble figuring out what this was aimed at. My comment was aimed more towards what the website can do and how it formats numbers when a user enters them.

Building in accessibility is a net win to all users, even those who think they may not directly benefit, spacing things out in a reasonable and predictable way helps everyone and especially those with eyesight, memory, and attention issues.