Be it seconds or milliseconds, eventually your program evolves to need tenths or less of that unit and you can either support decimal points, create a new field

Be it seconds or milliseconds, eventually your program evolves to need tenths or less of that unit and you can either support decimal points, create a new field and deprecate the old one, or do a breaking change that makes the poor SOB that needs to validate a breaking change-bearing upgrade in production before turning it on get a migraine if they have to toggle back and forth more than a couple times. Code isn’t always arranged so that a config change and a build/runtime change can be tucked into a single commit that can be applied or rolled back atomically. All because someone thought surely nobody would ever want something to happen on a quarter of a second delay/interval, or a 250 microsecond one.