When it comes to birthdates frequently it's possible to know that a person might be born between 1750 and 1850. Currently it's only possible to record such a value with a precision of thousand years. If it would be possible to state a timespan it would be much better.
The same goes for events where we know that a person was age X at year Y. In those cases we know their age with more precision than a decade and it would be good to state it with that precision.