For example if you had a water pokemon out and your opponent sent out an electric what would you do? Unless you want your water type to faint or you have a strategy to counter electrics somehow you're probably going to switch. And most likely to a ground type Which wouldn't be effected by your opponent's electric attack. Or a grass type that would take little damage. Of course if you are using the electric You should recognie the opponent will switch. You can use this opportunity to switch yourself or Use a counter move if you have one. Now one of the things that really sets gold and silver apart is that the attack hidden power can give any pokemon an attack of a max 70 base power of any type. Because of this you can never be totally sure that your opponent doesn't have a move to counter it's weaknesses. In electrics this is often of the Ice, Water or Grass type so in the electric example. If you anticipate a switch and your electric has a water, grass or ice hidden power then it can Use that move in anticipation of a switch and faint the ground type before it knows what hit it. You can also try to Fake out an opponent by using what might look like a standard set. With some key modifications to trip them up! This is where using underused pokemon can be helpful because it will be difficult for your opponent to predict you. So being unique and creative CAN help you at times.