When a SCD Type 1 is processed using the APPLY CHANGES INTO (or APPLY FROM SNAPSHOT) APIs there are not columns like the  "__CreatedDateTime" and "__UpdatedDateTime" automatically created in the structure and maintained through the APPLY. 
That is unlike the SCD Type 2 where "__START_AT" and "__END_AT" columns are automatically created in the table structure and maintained through the APPLY. 

The use case for having the SCD Type 1 including the something like an automated  __START_AT (original creation of the record .. which does not change) and __UPDATE_AT (from latest update of the record) is that it would allow simple identification of what records were first created and last changed which can be utilized downstream or to summarize the activity within the object since previously run.