Poor Flareon was done dirty by the mechanics of the first few generations. When a Pokémon uses a move of its type it gets a lot stronger, so any fire move Flareon used would be more powerful. Flareon also has a lot of physical attack, so it wants to use fire moves that hit physically.     The only issue is that before gen 4, moves were classified as "physical" or "special" not inherently, but by their type. So every single fire move (including Fire *Punch*) was a special move, which Flareon could not use effectively. Throw on top of this a super shallow move pool of lackluster coverage and you could see why Jolteon or Vaporeon saw a lot more usage.     They eventually additionally gave Flareon stronger moves on top of the physical and special split