string_zeroes takes a real value and returns it with 0s at the front until the total number of digits in the string is a number you define.
This is useful for a few different things. Most practically, displaying time. Digital clocks will show the time of "five minutes past eleven" as "11:05", not as "11:5". You can use string_zeroes(minutes,2) to quickly make this accurate while leaving a time like 11:32 unaffected.
It's also handy for retro games, where the score is always displayed as a set number of digits. See for example Super Mario Bros, where time is displayed as something like 500, 092 or 001, and score is 000500, 001000 or 219500.