Historical aggregation is different from the full rebuild of the reporting database.
As state on the links you provided, Re-aggregation of historical data happens on historical interactions which is interactions that have not been aggregated into the Experience Analytics reports while a full rebuild of the reporting database, it is the re aggregation of all interactions that have already been processed.
Now, it all depends on what you want to achieve. If you have imported historical data and require them to be present in the Experience Analytics report, then the historical aggregation is the option.
Normally, you’ll tend to perform a full rebuild of the reporting database if you have data inconsistency in the xdb.