What’s wrong with this picture?
Here is a screen shot from a bank’s website. Do you see anything wrong with it?
Of course, the answer is yes. This website is artificially constraining a wide variety of valid Internet users from entering their valid email address into the web form. Users of domains like .travel, .jobs, .tv or .ca would have a hard time entering their name into a form like this.
As a result of problems such as these, ICANN has been developing a toolkit for application developers so they can use more robust techniques for verifying the validity of domain names. The aim of the toolkit is for software developers to be able to accurately test for valid top-level domains and ensure that the situation above does not occur.
Whilst it is not clear to me why a credit card application needs to be so structured, if they choose to do so, it makes sense that they do so in a way that will not disadvantage users of specific top-level domains.