Annoyance: name fields with insufficient character limits

This is just something that comes up once in a while. How is it that the name field on a payment form can ever be limited to fewer characters than I have on my card? Should there not be a standard maximum number of characters, agreed for practical purposes, by card issuers and entities wishing to take payments? I have seen cards with only initials and a surname, and I have seen cards with a salutation as well as all given names in full before the surname, from the same issuer. It does seem a bit haphazard, but it doesn't seem reasonable to me that it should cause a problem, as long as it all fits on the card.

How does a person designing a form decide how many letters is too many? Is there some hidden cost to these characters? Does it require work to generate the capacity to receive each additional character? I don't understand the motivation.

Would be less annoying if it the instructions weren't explicitly "enter name exactly as it appears on card." I have encountered this online and on paper. If it's an entity I don't have a choice but to deal with, then perhaps the only consequence is my discomfort in trying to follow impossible instructions, or perhaps someone in an office somewhere has to spend time manually reading a form that a computer should have been able to read. If an online shop's payment interface makes my purchasing experience stressful, my business will go somewhere more confidence-inspiring.