"Click-it or Ticket" Rant

I don't understand the "Click-it or Ticket" campaign. It makes no sense to me. I recently attended a driving class to get out of a ticket. The question was asked of the instructor if one can be pulled over for not wearing their seat belt. The instructor unhesitatingly answered, "No." He said that not wearing your seat belt was a "secondary offense", but that it's very easy for a traffic officer to find a "primary offense" of which to stop you, in order to ticket you for not wearing a seat belt.

Here's the confusing part. Not signaling a turn is a primary offense. Not coming to a complete stop at a Stop sign is a primary offense. Not having both taillights functioning properly is a primary offense. YET, I see no billboard and commercial campaigns, costing taxpayers untold amounts of money, to deter those offenses. They are PRIMARY after all, meaning they are by definition GREATER OFFENSES than not wearing your seat belt. Right?

Of course, wearing your seat belt should be one's choice. It doesn't put anyone else in danger but yourself, unlike, supposedly, the aforementioned primary offenses. So why the campaign? Why the use of resources on deterring a lesser offense? Why is the government running our roads at all?