Reaching both people in a household used to mean two sends from the car, or waiting until you were back at a desk. Now the household screen has a group option for text and for email, with your templates available in both.
Sends log to the journal as one activity against the household, so the record reads the way the conversation actually happened rather than as two disconnected entries.
More on why ZachCRM is built this way: why your 2,000 contacts are really about 900 households.