It’s been a very long time since I’ve used Kernel#Integer, but to my recollection it was simply coercion that raised an error if necessary, as an alternative to things like String#to_i which would simply return the first digits in a string, or 0 if the string did not contain a valid integer.

Since the program I was writing was receiving amounts in the form of strings representing cents, I figured it would be a natural fit. Leading zeros would be stripped off of anything under a buck, and I could simply rescue any ArgumentError and handle them appropriately....