One thing you might be overlooking is that the French expertise at fighting insurgents of any type was increasing with experience. The Calabrians were eventually suppressed and the toughest insurgency the French would face would be in the Tyrol in 1809-1810, including the Spanish. An insurgency has to be supported by a regular army to be successful, as in Portugal and Spain. Wellington's army kept the Spanish guerillas alive and without it they would have been suppressed just like the insurgencies the French had faced before.

The one big advantage the Spanish insurgency had was that it was unexpected by the French. Baylen didn't help.

Back to Smith and his advantures-it should be noted that his exploits were in secondary theaters and had little or no contribution to the main efforts elsewhere. Both Egypt and southern Italy were secondary theaters with the 'main events' taking place elsewhere.