A live action superhero show before the wave of the netflix marvel shows and the CW superhero shows.
It started out as a reflection of it's time. It was a superhero take on the booming high school drama show in the style of buffy, veronica mars or roswell.
As the show evolved it reflected the revolution in live action superheroes that was happening in the mid 2000's. It marked the transition of these shows from a cute gimmic to what we see today with The Flash and Supergirl and Jessica Jones. None of these shows would be the same without Smallville to break the ground. It lasted for 10 seasons because even though it completely changed genres in season 6, it mastered both of those genres.