I learned that we could get rid of the return as well to have the best practice :)

This solution is no longer valid and fails the given test cases.

this doesn't verify the cases where the words differ in length by 1 character and this character is either at the beginning or end of the longer word.
eg: "1apple", "apple" or "fantastico", "fantastic"
the exercise clearly mentions such cases must return true
your function would compare left to right and find that all the characters are different from the very first index onwards, and return false.

Swift translation kumited: https://www.codewars.com/kumite/58acfc1d1541656201000062?sel=58acfc1d1541656201000062