Like using the Missingno glitch to get infinite TMs of strong moves like Earthquake and Blizzard or even good items like Rare Candies or Master Balls. Or to catch some rare Pokemon early on, like getting a Lapras or Scyther before Misty, using an extension of the Mew glitch. Or even exploiting things in battle like Hyper Beam not recharging if your opponent is defeated. It's not like it is one sided. For instance, Focus Energy lowers your critical hit instead of increasing it. And a glitch causes moves other than Swift (and in the Japanese versions Swift is not immune) to potentially miss. If the game is unfair with its own rules, is it not fine to exploit for your benefit, given it is not like you are using any external devices? And many young kids might not have realized the developers did not intend these to happen and just used them on discovery.