The Date Question: low ball vs. mint error

Why do low ball coins need to be assignable to a date to straight grade when mint errors don’t?
0
Why do low ball coins need to be assignable to a date to straight grade when mint errors don’t?
Comments
Because you can't build a low ball registry set out of dateline coins.
Also, error coins are "as struck" while the worn coins are not.
It is also not 100% true. One year type coins can be graded without a date.