How to set a default for a date in a workflow NOT JAVASCRIPT

When using dynamic values to populate fields in the Update record Action on a CRM workflow you get this:

There are fields show for setting a default.

However,  those fields are always inactive.  not useable.  no matter what I select those fields cannot be used.

QUESTION: Is it possible to set a fixed date or date/time (12/31/9999) into a date field in a CRM workflow?

I know how to do it with Javascript or a business rule.  This is probably just another of the many things that M$ just did not address when creating Dynamics 365.