Why do Credit Cards enjoy so copious digits/numbers _-_-_-_-_-_?

Answers: The first part of the number identify the type of card and the bank that issued it. Only the final half is matchless to the individual account. Most cards hold one or more check digits built in to detect typos. This borders the number of available account numbers. Less that 16 digits would not provide plenty unique numbers to shift around.

because they have so heaps accounts,that they have to do that surrounded by order to spread them out & not enjoy to many near ### close to the same.

So they don't run out of numbers and hold to duplicate account numbers. There are masses people near current or previous accounts.