It may be as a safety measure, it's much less likely to misuse the setter if it's divided into two different functions. If it's just one function you need to co

It may be as a safety measure, it's much less likely to misuse the setter if it's divided into two different functions. If it's just one function you need to constantly ask yourself "wait, am I setting a function or not?", unless you always want to write `$a(() => value)`, which would be pretty ugly.