[fragmede]

I'm going to guess that this will actually convert better because it helps answer the most important question a user asks:

Did I enter my freaking CC number right?

For those hunt and peck typists, the larger size, the proper handling of spaces, and the ease of comparing to the actual card makes that so much easier, even for the average users.

I will note that the expiry and name input could be highlighter better - I missed the expiry until I accidentally clicked on it.

For those power shoppers who've memorized their card number, this will still work for them too.