There are times when you want to know if a value has never been set before. For example, if you want to use a default value if it has never been set, but if someone has edited the post and removed the default value then show nothing at all.
$value = get_field('some_field');
if ($value === NULL) {
// show default value
} elseif ($value) {
// show value from field
} else {
// show nothing
}
There are probably many conditions where it is important to know if a value has never been set or the field simply does not have a value.
