You cannot drop a temporal table while it is performing the versioning. You first need to disable that to do a drop. It is possible to alter existing tables to become temporal. You will need to provide default values for the required temporal table columns (ValidFrom, ValidTom, and Period).
Once you have the versioning on, then you can query values in the table between certain timeframes. This let's you look back at the value that columns had previously. This is useful and acts like an auditing system for changes in column values.
