The Specialized Tarmac is for those who quite simply want one of the best road bikes available. An aero road bike built for speed yet comfortable enough to spend all day in the saddle, all in an extremely light package.
We use the bike, in this instance more like a fine wine being paired with a insatiable cheese. Something like a semi soft Gruyère or Comté and a nice Pinot Noir. The Tarmac and (bias opinion) best cycling saddle bag are a winning combination.
As Whitney states, the purpose of a saddle bag on your bike is "to be able to fix the most common mechanicals you're gonna encounter on the road"
This would be the absolute minimum you would want to bring with you on a ride. If you pay attention to most professional gravel racers, this is the minimum that they race with as well.