Mostly for the count, I will use Adhoc Analysis or Workspace to get the count : One Row = One Unique Count. Easy and simple way!
But the above wont help if you have (Low-traffic) grouped into one line.
So, if you have (Low-traffic) grouped into one line, you should go only to Data Warehouse. No other go!
And you can do this advanced implementation using getValOnce with an event assigned to it and set the expiration to 30 days. Now, the event count will get you the unique count for the period of 30 days.